For the longest time, Call of Duty was my favorite first-person shooter franchise. And no, it certainly wasn’t for the compelling storylines in the single-player campaigns. I truly enjoyed the competitive nature of multiplayer. In fact, I was good. I had an ego that rose with my kill-death ratio. Looking back through my Steam screenshots folder, I still hold on to a few good screencaps, namely one on Crossfire with over 100 kills and just a handful of deaths. It was a glorious time. I fell away from the series, though. I abhorred the jetpacks and mechs–the futuristic setting–that new games brought forth. I wanted the old-fashioned boots-on-the-ground experience once more. Well, this year I’ll receive my wish, as will many others.

You know what, though? The gameplay wasn’t the only thing that drew me in. It was the attention to detail. The little tidbits are hidden throughout each map. Easter eggs, if you will. Each developer included something unique; they wanted players to explore and find enjoyment from the trivial things. That worked, too. There were teddy bears scattered throughout levels, ghostly songs played just out of range, and even jump scares in a genre severely lacking in them. They were secrets. They were meant to be hunted and explored, to be discovered by the online community and shared with the world. Some took years to discovers; others, the more commonplace secrets, were found within days of release.

Without further ado, here are 20 Call of Duty secrets they don’t want you to know about…or do they?

20 Ranting And Raving

The Dome was a popular multiplayer map in Call of Duty: World at War. It’s based on the final portion of the single-player campaign, the rooftop and dome of the infamous Reichstag. In the campaign, we see this building in “Downfall.” Now, the development team had some fun with this location. As I said, it was infamous. It was a meeting grounds for the Nazi war machine, including all manner of propaganda.

Casual players may not discover this secret. If you head to the edge of the map, where the Nazi flag flies over the building, wait just a moment. You’ll just barely make out the noise of Adolf Hitler’s famous rally speech. He’s rambling on to a broken and empty city, and it’s quite eerie.

19 Seeking Asylum

You know, hearing someone crying and not being able to find the source is less saddening and more terrifying. Imagine wandering through a deserted building, and the only sound you hear is a woman crying. That’s a good “nope” moment.

In The Asylum, another multiplayer map based on the Russian campaign in Call of Duty: World at War, you’ll hear just that. This map is war-torn, dirty, and terribly creepy. First, you’ll hear a piano playing on the top floor. There is no one around, nor are there any musical instruments available. The second secret is the infamous crying woman. Wander into the bathrooms, walk by the stalls, and you’ll hear her. Stick around long enough, and you’ll hear a man’s voice speaking in an unknown dialect, assumedly to the woman.

18 The End Chants

Continuing the trend of World at War’s multiplayer maps, Cliffside plays host to none of the more frightening secrets. It’s terrifying because of the unknown. There is one area of the map that plays host to an open, aboveground coffin in a concrete tomb. The atmosphere is creepy enough. Venture inside. Once you’re inside, listen for the beast. At first, most thought it was merely music playing in the background. That’s not the case, though. Listen carefully. You’ll hear voices, like some type of chanting. Over time, the chanting will become louder, more pronounced.

The source of the chanting stems from the empty casket. It’s a male’s voice, chanting ominously in an unknown language. He’s summoning demons. Lucky for you, no demons will be brought forth.

17 The Resistance's Raygun

Everyone wants the raygun. It’s the most favored weapon in the cooperative zombie mode. And for a good reason. You see, the raygun is a one-hit-kill weapon. Aim at an opponent, pull the trigger, and you’ll be rewarded with an immediate kill. It’s that simple. Typically, this gun is only meant for the cooperative game mode, though. With this secret, that’s not the case. You can find the infamous weapon in the “Little Resistance” campaign mission of World at War.

To get the raygun, start near the crate at the rightmost portion of the beach. Jump into the crater for a few seconds, then jump out. Do this repeatedly, moving from one crater to the next; all while headed towards the left side of the beach. At the final crater, look forward and wait a couple of seconds. You’ll hear an odd rumbling noise; the map will shake, then a demon voice plays. The Raygun will rise from the ground in the mouth of a stone dog.

16 Sanctuary Spirits

Let’s break the cycle a little. We’re headed to Call of Duty: Modern Warfare 3; arguably one of the better games in the franchise. While playing on the Sanctuary multiplayer map, you may just stumble across spirits.

Turn your attention to the grass. At random intervals, you’ll notice purple flowers marking various spots. If you lay prone by these flowers, you’ll hear the voices of a man, woman, and children. This family was killed during “Davis Family Vacation”–the single-player mission. The voices are them reliving their last moments alive. It’s a sad, eerie moment in an otherwise frantic game. It’s tough to make out all the words, though. You’ll mostly hear the tone of their voices. It’s ghostly.

15 UFO House

Game developers, for whatever reason, love to include aliens and UFOs in their video games. The setting and world may not be inclined towards the unknown, but that doesn’t matter. In Call of Duty: Finest Hour–one of the earliest games in the series–you’ll find just that. Aliens.

In the back room of one house, on the “Come Out Fighting” single-player level, along the right side of the house, you’ll find a window. Here, the player can shoot the machine gunner firing on them while coming inside. Head back downstairs, then outside. Jump past the sandbags and onto the barbed wire. Follow the wire to the house, then through the wall and down a hallway. Inside, you’ll find a Nazi UFO stashed away and four health packs to ease your journey.

14 Walking With The Dead

Zombies have always been a big part of Call of Duty, ever since their introduction in World at War. Since that release, we’ve had some iteration of a zombie cooperative mode every year. It’s fun…for some. Others, however, want to take their zombie entertainment to the next level. Call of Duty: Advanced Warfare allows just that.

In multiplayer, it’s possible to unlock clothing and headgear to turn your character into a zombie. The armor and skin combo is quite lovely, albeit rare. Most people are just too busy trying to rank up to unlock new gear. Basically, to unlock each piece of zombie equipment, you need to complete the Exo Survival mode in its entirety, including the secret zombie round. Doing so will net you each piece.

13 Who's The Doctor?

In the world of video games, it’s easy to be a fan of geek culture, including television shows and comics. One such show is Doctor Who, a favorite amongst countless people across the world. Seriously, it’s impossible to count that many. Call of Duty: Ghosts’ dev team is certainly no stranger to the weird and geeky.

In the campaign mission “Struck Down,” you’ll stumble across a broken trophy case with a few choice pieces still inside. One such trophy is an homage to Doctor Who. It reads “Largest Interior with the Smallest Exterior,” and is shaped like the T.A.R.D.I.S.; Doctor Who’s time-traveling space ship. Another trophy, just beside the police box, is shaped like a Rupee, the gems found in The Legend of Zelda, and reads “Most Bushes Cut and Pots Smashed.”

12 The Man Of Many Faces

Lieutenant Dimitri Volsky, an officer in the Red Army’s 13th Guards Rifle Division, fought in the battle of Stalingrad. He was a unit leader throughout the Soviet campaign in Call of Duty 2. For all intents and purposes, he appears to be good friends with Vasili. However, Dimitri has something charming, albeit downright odd about him.

In the early levels, Dimitri has the traditional Commissar uniform to designate him as an officer in the Red Army. In “Comrade Sniper,” however, he can be seen with a completely random uniform and face. The man literally changes his face. This wasn’t an Easter egg, though. It was, in fact, a mistake by the developer that they would surely prefer everyone forgot. That won’t happen anytime soon, though.

11 Sympathy For The Devil

Nuketown is a fan favorite. Always has been, always will be. That’s why the developers keep remastering the multiplayer map for each release. Call of Duty: Black Ops was famous for it, though. It all started here. Of course, there were secrets. Secrets that the development studio hid quite well. The community is what it is, though, found each secret in time.

Have you ever noticed the mannequins? Creepy, right? Well, if you shoot their heads off within 50 seconds, you’ll be rewarded with Rolling Stone’s “Sympathy for the Devil.” It’s the same song you heard during the campaign. It’s probably not the most rewarding of secrets to discover–you can find the song on YouTube quite quickly–but it’s still worth completing just for the bragging points.

10 Throwback To The Classics

As I said, they remaster the Nuketown map quite often. In Black Ops 2, the mannequins return, and this time they have a new secret hidden within. Again, you’ll be shooting at the dummies to unlock something unique.

In this iteration of the map, shoot the heads off all the mannequins on the map within two minutes of the start of the match. If accomplished, the screen will display an Activision logo in retro style. You’ll then be able to approach and play classic Atari games, including Pitfall! H.E.R.O., Kaboom!, and River Raid. While playing, you’ll be completely invulnerable–no one can hurt you. Enjoy your time playing classic video games inside of a video game. Remember to screenshot or record the interaction; otherwise, no one will believe it really happened.

9 The LOL Aliens

You’ll need the Call of Duty: Ghosts DLC to find this secret. Specifically, Extinction Mode. If you play on the cooperative map “Point of Contact,” the Easter egg is relatively easy to discover. To activate the secret, simply take a moment from the chaos to shoot the “L” and “O” letters on “Lodge” on the Gils Lodge Motel Sign. You’ll want to spell “L-O-L.” If done right, and fast enough, you’ll receive a LOL popup on your screen, indicating the beginning of the Easter egg. From there on out, every time you kill an alien, it will explode into alien toys. This secret does time out eventually, but you can repeat the sequence multiple times. It’s perfect for everyone to have a try. So, give it a shot!

8 The Teddy Bear Is Adorable

Since the very first release, Activision has tossed in teddy bears. So far, they’ve been found in twelve releases, from Finest Hour to Black Ops 3. The very first appearance was in Call of Duty: Finest Hour. During the mission “Underground Passage,” you’ll find a room containing a teddy bear. Pick it up and you’ll receive a message, “The teddy bear is adorable,” and your health bar will be refilled. This is, sadly, not the case for every teddy bear in the franchise, though. Some are just for show, while others will offer health replenishment.

To some, finding the teddy bears is a personal achievement. To snap a screenshot of one is a rite of passage for long-time fans of the series. Can you find them all?

7 The Ultimate Power

With the introduction of Nazi Zombies, Activision also introduced unique characters to the multiplayer portion of the games. In World at War, these characters were simple soldiers from different factions of the war. Today, they’re a little zanier.

If you take the time to delve into these characters, you’ll find a hidden message scrawled throughout their biographies. The message reads "The Dr. Wants The Ultimate Power Bastard.” The message is hidden, though. Basically, take the first letter from each sentence to spell out the meaning. The word “Bastard” can only be found in Richtofen’s bio, while the rest have “The Dr. Wants The Ultimate Power,” hidden throughout their biographies. The overall meaning is unknown, however. Sure, people may speculate. In the end, only the development team can truly say what they meant here.

6 We All Fall Down

“We All Fall Down” is known as the death song and is also a musical Easter egg on Die Rise, one of the community’s favorite zombie maps. Sung by Clark S. Nova, you may play the entire track either in the main menu or at the Safe House using the built-in music play in Black Ops 3.

In Black Ops 2, the song is hidden within the game. You’ll need to find three teddy bears (see, they love those bears) in-game. The first is lying on a shelf beside the SVU-AS sniper. The second is sitting on a sewing table in the power room. The third, and final, is in the far left corner of the upside-down restaurant. It’s a pretty straightforward secret, and relatively easy to find once you know what you’re looking for.

5 These Are More Dangerous Than The Zombies

We all know Facehuggers. At least, we should. The Alien franchise is one of the premier science-fiction stories. In Black Ops 3, there is a reference to the franchise. While playing the Zombies mode, on “Shadows of Evil,” you may just stumble across a Facehugger of your own. If you don’t know, the Facehugger is a Xenomorph, about 3-feet in length, and attaches to the face of its victims.

Inside the Mystery Box, if you look carefully enough, you’ll notice the infamous Facehugger nestled inside the rightmost “slimeball.” Furthermore, after completing the Pack-A-Punch ritual, you’ll hear a secret message from Dr. Maxis. All-in-all, these little secrets are pretty interesting to discover. They feed our inner desire for more science fiction and horror. Such a reference is always welcome.

4 This Cow Is Just So Big

Cows are another running gas hidden throughout the Call of Duty franchise. Much like the teddy bears, there are numerous instances of cows seen throughout the games. In the earlier games, with levels taking place in Normandy, the developers liked to joke around a little. They put “no cows were harmed in the making of this game” in the credits of their first and second game.

That’s not all, though. In Call of Duty: United Offensive, on the “Crossroads” level, you’ll stumble across the “Giant Cow.” It’s named as such due to its stature, which is oversized. They even went so far as to increase the size of the bell hanging around its neck. A minute detail that we’re quite happy to see. Now, no one really understands the fascination or running joke with cows, but then again, we don’t really need to either.

3 Wanted: One Noob Pwner

The “Noob Pwner” should be infamous by now. If you’re playing Call of Duty: Black Ops, specifically the Escalation DLC map, you’ll stumble across a few wanted posters on the walls. One such poster describes a 14-year-old boy, wanted for “pwning noobs and being awesome.” We’re not sure of this kid’s kill-count, but it certainly must be high to warrant an in-game poster.

In reality, the kid is supposedly one of the developer’s boys. These folks work hard on video games designed to bring us entertainment. Sometimes, their demanding work is at the expensive of their families. As such, it’s nice to see someone recognize their son in-game, a little tribute that he no doubt say while playing the game himself. At least, we hope he saw it.

2 Watch Out For The Nuketown Angels

Remember the trophy case from Call of Duty: Ghosts? More specifically, do you remember the Doctor Who reference? Well, they’re at it again. In Call of Duty: Black Ops 3, on “Nuketown 2025,” there is yet another clear reference to the science fiction series. It’s a terrifying one, too.

This time around, if you shoot the arms off the mannequins, they’ll come to life. Stare at the mannequins, and they’ll remain stationary, unmoving and yet staring at you. If you turn your back; well, prepare to run. As soon as you look away, the mannequins spring to life and will chase you down. Oh, and you’ve got just two minutes to shoot the mannequins’ arms off to initiate the secret. Better be quick!

1 When Call Of Duty Turns Into A Horror Movie

We’re returning to Call of Duty: Black Ops 3 one last time. In the introduction, I mentioned jump scares in a genre that wasn’t known for having scares. Well, here it is. If done right, you might find yourself falling from your chair.

While playing the “Origins” map, head over to the Pack-A-Punch machine. It’s on top of a destroyed structure, with stone statues rising out of the ground. Head to the corner; the one facing the broken-down church in the distance. Now, this secret is best accomplished with a sniper rifle. One with an enhanced zoom function. Scope in on the tower, towards the left. Wait a moment, and then enjoy the jump scare that ensues.