Among the eight schools of magic present within Dungeons and Dragons, transmutation spells cover those incantations that change the properties of a person or thing. This change can be as small as making metal glow hot, or as big as turning a horse into a newt. Whatever the thing or person was, after casting transmutation magic on it, it's undeniably been altered.
But which alteration options are among the creme de la creme? This list is comprised of the most useful transmutation spell options of levels 4th and below. Higher-level spells have been excluded as they are only available to less common, higher-level characters. Furthermore, their high-level spell slot requirements make them innately powerful.
10 Thaumaturgy
The tried and true cantrip thaumaturgy. If you've played a spellcaster in Dungeons and Dragons, chances are you've tried to convince an NPC of something using this cantrip. Depending on the dungeon master and the thoughtfulness of your attempt, you either awesomely succeeded or failed spectacularly. As an action, thaumaturgy creates one of numerous effects. These effects include a louder voice, flame alterations, harmless tremors, a sound that originates from a point within 30 feet, opening or closing a window or door, and changing your eyes. One thing most players overlook is that you can have up to three of these effects active at one time. Thaumaturgy is a roleplaying gift from the DnD gods, no matter its benign cantrip status.
9 Gaseous Form
In comparison to the well known and often used cantrip thaumaturgy, gaseous form may as well not even exist. Despite years of Dungeons and Dragons play, we've only seen it cast once, and to great success at that. Unfortunately, the casting ended in inevitable death during a one-shot of the original Tomb of Horrors module. But that's beside the point. Gaseous form is a 3rd level concentration spell that, as an action, turns a willing creature and all its belongings into a misty cloud for an hour.
Your only action while in this form is a flying movement of 10 feet, but you can pass through small holes, narrow openings, and mere cracks. As far as infiltration attempts are concerned, gaseous form might be even better than invisibility. It's a shame that most games don't ever get to see it cast.
8 Enlarge/Reduce
Enlarge/reduce is a 2nd level concentration spell that does exactly as it implies. You choose a creature within 30 feet and its size either doubles or halves. An unwilling creature gets to make a constitution saving throw. On a success, the spell does nothing. A creature who is enlarged gains advantage on strength checks and saving throws and their weapons deal an extra 1d4 damage. A creature who is shrunk suffers these benefits as deficits instead. Perhaps most importantly, the spell changes the target's size category by one degree. This makes huge creatures more easily restrained and gives small ones a harder time escaping.
7 Heat Metal
Here's an inventive spell that's applicable in a wide variety of situations. Heat metal is a 2nd level concentration spell that causes a metal object within 60 feet to glow red-hot. A creature within contact with the object takes 2d8 fire damage upon the cast. Additionally, if the creature remains in contact you may cause the damage again as a bonus action on subsequent turns. But that's not all. If a creature is holding or wearing the object, they must make a constitution save as well. On a failure, they drop the object if they can. If they don't drop it, they have disadvantage on attack rolls and ability checks until the start of your next turn. That's a lot of oomph for a 2nd level spell. It deals damage to your opponent, possibly disarms them, and, if not, incurs a backbreaking penalty. Needless to say, be on the lookout for metal weapons and armor.
6 Slow
Speaking of backbreaking penalties, slow is the perfect spell for causing them. Its a 3rd level concentration spell that alters time for six creatures inside of a 40-foot cube within a range of 120 feet. Targets must succeed on a wisdom saving throw or else suffer the following: half speed, - 2 to their AC and dexterity saving throws, and the inability to use reactions. Worse yet, on their turn, they may only take a single action or bonus action, not both. Regardless of their abilities, they can only make one attack per turn.
Finally, if the target attempts to cast a spell with a cast time of 1 action it must first roll a d20. On a result of 11 or higher, the spell doesn't take effect until their next turn and they must use their action on that turn for it do so. If you can manage to maintain your concentration, slow is an utterly debilitating penalty for any opponent to deal with.
5 Alter Self
Those last two spells were a mouthful. About time we get back to simpler transformations. Alter self is a 2nd level spell that changes your appearance for one hour. You can give yourself gills, grow claws, or, most popularly, look like somebody else. Alter self is a spell as essential to the game of Dungeons and Dragons as fireball, but it operates on the axis of roleplay instead of combat. There is some irony in a player's excitement to become another person in a game where they've already become another person, but who are we to judge?Anyway, it gets players thinking about the game in a different way, which provides a breeding ground for creativity.
4 Levitate
Like gaseous form, levitate is another underutilized spell. Its a 2nd level concentration spell that, as an action, causes a creature or loose object within 60 feet to rise vertically, up to 20 feet, and remain suspended there for up to 10 minutes. The spell can levitate targets up to 500 pounds in weight. You can change the target's height by up to 20 feet up or down on your turn, and the target can only move by pushing or pulling on a nearby surface. An unwilling creature that succeeds a constitution save is unaffected. Besides usage on yourself for crossing perilous areas, levitate provides intriguing roleplay and combat implications that we encourage players to explore.
3 Zephyr Strike
But enough about experimentally good spells. Sometimes you want a spell that just gets the job done. Zephyr strike can be counted among these. It's a 1st level spell concentration spell that, as a bonus action, prevents opponents from making opportunity attacks against you. Additionally, once before the spell ends you may give yourself advantage on a single weapon attack roll. If the attack hits, it deals an extra 1d8 force damage and, whether you hit or miss, your walking speed increases by 30 feet on that turn. Zephyr strike is a simple yet powerful spell that makes a great addition to any ranged character's arsenal.
2 Haste
Whereas slow provides a brutal debuff for your opponents, haste does the exact opposite. Instead, transferring a considerable boon to an ally. Haste is a 3rd level concentration spell that, as an action, infuses one creature within 30 feet with unparalleled quickness.
While active, the spell bestows the following benefits: double speed, + 2 to AC, advantage on dexterity saving throws, and an additional action. This additional action can only be used to make a single weapon attack. Throw haste on your party's biggest threat and take pleasure in the mayhem that ensues.
1 Polymorph
How could we talk about transmutation spells without mentioning polymorph? As the indisputable king of transmutation magic, polymorph has a wide variety of applications. All of them are devastating. Polymorph is a 4th level concentration spell that requires a creature within 60 feet to make a wisdom saving throw. On a failure, they are turned into a creature of your choosing for one hour. This creature can be any beast whose challenge rating is equal to or below the target's level. The target assumes the hit points of its new form. Whether it's turning your ally into a death-dealing giant scorpion or reducing an enemy to the form of a snail, polymorph is sure to bring memorable moments to a tabletop near you.