The purpose of armor, obviously, is to protect your body. You strap a big ol' hunk of metal to your chest, then nothing's going to be able to stab or shoot you there. But what happens when you want to take the armor off, and the armor... disagrees?
A good number of game characters, either temporarily or permanently, have found themselves trapped in some form of armor or bodysuit. They may still be mobile, but their bodies — or even their very souls — are completely constrained to these metallic shells. Generally speaking, it's not a very pleasant way to live. We feel for these examples.
10 Ghost People - Fallout: New Vegas
Before the Great War of the Fallout universe, the workers of the Sierra Madre Casino and resort were accidentally exposed to a leak of the gas that would eventually form the corrosive red Cloud that covers the area. To protect them, they were issued specially-made hazmat suits and masks, but their shoddy construction would relegate them to a fate worse than death.
When the Cloud descended upon the Sierra Madre, its corrosive chemicals rusted the clasps on the hazmat suits shut, while wisps of it snuck into the suits through the joints and mask. This resulted in the Ghost People, a race of mysterious, undying mutants who have been hermetically sealed into their suits. Forcefully opening the suit, such as through dismemberment, releases pockets of pressurized gas, killing them instantly.
9 Big Daddies - BioShock Series
Originally, BioShock's "Big Daddies" were just regular members of Rapture's maintenance staff. As Rapture was at the bottom of the ocean, maintenance crews needed heavy diving suits to re-rivet Rapture's windows or drill ocean rock. When the Little Sister program was launched, these suits were repurposed to create their faithful, lifetime protectors.
A protector-grade Big Daddy is created through a combination of severe Splicing and invasive surgical procedures, all to physically graft the skin and organs of a suit's occupant to the suit's inner linings. Why they chose to make this a permanent process isn't stated outright, but we can make an educated guess — since most of the Big Daddies used to be convicts, their creators probably didn't want them blabbing to anyone about their origin.
8 Quarians - Mass Effect Series
Technically speaking, the Quarian race of the Mass Effect series aren't "trapped" in their enviro-suits, at least not in the literal sense. They can take their suits off whenever they please. It's just that, due to their species' naturally weak immune systems, doing so would almost immediately result in debilitating illness, followed by death.
Quarians can never remove their suits unless it's for a very good reason, such as a medical procedure. Even then, they need to undergo a lengthy trial of vaccines and antibiotics just to offset the risk of sudden viral death. Sooner or later, though, the suit always has to come back on, even on a Quarian-owned vessel. The proliferation of microorganisms throughout space is just too thorough.
7 Hakumen - BlazBlue Series
As the leader of the Six Heroes, Hakumen is a public icon — recognized, respected, and feared just about anywhere in the world. However, no one has ever seen Hakumen's face beneath the steely-white sheen of his armor. As it turned out, that's because he doesn't have a face under there.
Hakumen's armor is an ancient artifact known as the Susanoo Unit. In order to wear the Susanoo Unit, you need to give up your physical body and bind your soul to it directly. Only a supernatural entity like Yuuki Terumi can come and go from the armor as they please. A human soul like Hakumen's is stuck in there for life; the only way out is death.
6 Springtrap - Five Nights At Freddy's 3
In the lore of the Five Nights at Freddy's series, inventor-turned-serial killer William Afton murdered five children at Freddy Fazbear's Pizza and hid their bodies inside the pizzeria's animatronics. Many years later, after numerous run-ins with the animatronics, possessed by the children's vengeful spirits, Afton returned to the pizzeria and attempted to dismantle them.
However, Afton was cornered by the spirits and attempted to hide in the old Springlock Bonnie suit. It worked for a bit, but when the springs came loose, he was crushed within the suit. Many years later, Afton's corpse, still crushed in the suit, was recovered and utilized in the Fazbear Fright attraction, where it came to life with malicious intent as Springtrap.
5 Dingo Egret - Zone Of The Enders: The 2nd Runner
When Dingo discovers the derelict Jehuty while on a mining expedition, he has no choice but to commandeer it to defend himself from the BAHRAM army. After several lengthy encounters, he's forced into a conflict with Nohman and Anubis, which he ultimately loses.
After being shot in the back multiple times, Dingo was dragged back to Jehuty, where his body was integrated with the Orbital Frame's life support systems. At this point, Dingo can no longer leave Jehuty or remove his pilot suit, as its systems are quite literally the only thing keeping him alive. He also can't go against the orders of UNSF spy Ken Marinaris, lest she cut his life support remotely.
4 Y-17 Trauma Override Harnesses - Fallout: New Vegas
If we had a nickel for every instance of armor-based body horror in Fallout: New Vegas, we'd have two nickels. Not a lot, but it's weird that this has happened twice. Of course, unlike the Ghost People and others, the Y-17 Trauma Override Harnesses that litter the Big MT facility are functioning just as they're supposed to.
The idea behind these special suits is that if a combatant wearing one were critically injured, the suit would take over their motor functions and march them back to base for medical attention. Unfortunately, someone forgot to set a base in the suits' programming, causing them to just wander around aimlessly and shoot at people while their occupants slowly died. This is why Big MT is full of skeletons wearing spacesuits.
3 The Lingering Will - Kingdom Hearts Series
In the climax of Kingdom Hearts: Birth By Sleep, Terra confronts Master Xehanort atop the highest mountain of the Keyblade Graveyard. Blind with rage at Xehanort's deceptions, Terra lets darkness flood his heart, giving Xehanort the perfect opportunity to send his own heart into Terra's body to commandeer it.
This seems to work perfectly at first, with Xehanort in full control of Terra's heart and body. However, he missed one part: Terra's mind. With his last ounce of spirit, Terra's will animates his cast-off Keyblade armor to oppose Xehanort, though sadly he would ultimately fail to reclaim his body. The armor remained in the Graveyard for many years afterward, quietly waiting for a chance to exact vengeance.
2 Ratchet - Ratchet: Deadlocked
In Ratchet: Deadlocked, Ratchet, Clank, and their friend Al are kidnapped by Gleeman Vox to compete in the illegal gladiatorial game show, DreadZone. When Ratchet wakes up in his confinement block, he's already fully dressed in a set of DreadZone armor, including the program's signature explosive obedience collar.
If Ratchet is capable of taking his DreadZone armor off independently of his explosive collar, he never does so. More than likely, aside from the helmet, the armor is part and parcel with the collar — which means it had to stay on until Ratchet could defeat Vox and escape the show.
1 "Simon Jarett" - SOMA
In SOMA, modern-day everyman Simon Jarett goes in for an experimental brain scan to seek potential aid with a medical problem. The scan goes fine, and he presumably goes on with his life. Many, many years later, though, that scan of his mind comes to life as an entity of its own, with a huge gap in his memory.
Due to a computer glitch, Simon's old scan was downloaded into an AI-compatible deep-sea-diving suit, giving him control of it as though it were his own body. The body in the suit isn't even his; a woman died in it, and its automated systems synced his program with her brain. Technically, Simon can leave this suit by copying himself into another suit, but it's up to chance whether he's the one who perceives this change or just remains where he is.