Shapeshifting

Mystique — Alters appearance, voice and colouring but not her mass, which is the canonical limit on her power

Clayface — Has no fixed internal structure, so conventional injury does very little and containment is the standard countermeasure

Beast Boy — Transforms into any animal, extinct species included, but cannot leave animal forms or lose the green colouring

Envy — Impersonates specific individuals precisely enough to destroy their relationships from the inside

Martian Manhunter — Shapeshifts and phases through solid matter using the same underlying Martian physiology

Majin Buu — Absorbs opponents into his own body and gains their abilities and intelligence

Majin Buu — Reshapes his own body at will, including turning opponents into food

Majin Buu — Splits into separate beings with distinct personalities

Cell — Transforms through three distinct forms as he absorbs the androids

Cell — Perfect form is stated to be the ceiling of his design, not a stage

Apocalypse — Reshapes his body at will, including size and limb structure

Apocalypse — Converts parts of his body into machinery and weapons

Loki — Takes any form, including other characters, convincingly enough to fool them

Loki — Changes sex and species, which the source myth and the comics both treat as routine

Plastic Man — Takes the shape of objects, not just people — furniture, vehicles, machinery

Plastic Man — Changes colour as well as form, which is what makes the disguises work

Mystique — Takes any humanoid form down to voice, fingerprints and retinal pattern

Mystique — Cannot copy powers along with appearance, which is the ability's stated limit

Mystique — Holds an impersonation for months without detection

Envy — Takes any human form precisely enough to replace someone unnoticed

Envy — Reveals a true form far larger than any shape it usually takes

Clayface — Reshapes his body into any person, and holds the form under scrutiny

Clayface — Physical attacks pass through him without effect, so he is fought with cold or sound

Beast Boy — Becomes any animal he can picture, keeping his own mind

Beast Boy — Extinct and alien animals are within range, so the limit is imagination rather than biology

Elasti-Girl — Reshapes her mass into forms other than her own

Elasti-Girl — Her exposure to volcanic gases is the stated cause, not a mutation

Zetsu — Splits into black and white halves with separate personalities

Zetsu — Takes the appearance of others convincingly enough to infiltrate

Klaw — Forms solid constructs out of sound, including creatures

Klaw — Reforms after being dispersed, so he is difficult to kill permanently

Swamp Thing — Reshapes his body at will, including to enormous size

Swamp Thing — Grows a body on another planet from local flora

Mister Fantastic — Reshapes himself into objects — a parachute, a shield, a container

Mister Fantastic — Alters his face enough to pass as someone else

Juvia Lockser — Dissolves into water entirely and reforms elsewhere

Juvia Lockser — Traps opponents inside her own water form

Floronic Man — Reshapes his plant body into weapons and larger forms

Floronic Man — Regrows lost limbs immediately from surrounding plant matter

Elongated Man — Reshapes his face and body to alter his appearance

Elongated Man — Forms his body into tools and containers

Eren Yeager — Transforms into a fifteen-metre Titan by injuring himself with intent

Eren Yeager — Hardening lets him form solid structures from Titan matter

Eren Yeager — Holds three Titan powers at once, which no previous holder managed

Muzan Kibutsuji — Takes the form of a man, a woman or a child to move unnoticed

Muzan Kibutsuji — Reshapes his body into blades and whips mid-combat

Denji — Transforms into the Chainsaw Devil by pulling the cord in his chest

Denji — Chainsaws emerge from his arms and head, not from any weapon he carries

Denji — Fights devils many times his size and wins by aggression rather than technique

Erza Scarlet — Requip swaps her armour mid-strike from a pocket dimension

Erza Scarlet — Swaps armour faster than an opponent can adapt to the previous one

Erza Scarlet — Holds over a hundred armours simultaneously in storage

Venom — The symbiote forms weapons, tendrils and a full disguise

Venom — It carries the abilities of every previous host, including Spider-Man's

Venom — Mimics ordinary clothing well enough to pass in public

Carnage — Forms blades and spikes directly from his own body

Carnage — The symbiote bonded to Kasady's bloodstream, not just his skin, which is why separation fails

Carnage — Produces new symbiotes by seeding them, unlike Venom

Edward Elric — Reshapes his automail arm into a blade mid-combat

Edward Elric — Equivalent exchange binds every transmutation — nothing is created

Edward Elric — Repairs and modifies equipment on the spot rather than only attacking

Jiraiya — Summons giant toads that fight independently alongside him

Jiraiya — Fights Pain alone and identifies the mechanism before dying

Jiraiya — Uses hair and toad oil techniques that no other character replicates

Orochimaru — Sheds his body entirely and emerges from it renewed

Orochimaru — Detaches and reattaches parts of his own body at will

Orochimaru — The curse mark grants power to others at the cost of his influence over them

Kurama — Reverts to his true Yoko form, a silver fox demon

Kurama — The Yoko form requires enormous energy and cannot be held long

Ken Kaneki — Manifests a kagune from his back as a weapon

Ken Kaneki — Ghouls can only digest human flesh and coffee, a biological constraint not a choice

Kurama — Uses death plants that kill on contact without further direction