Known History
The history of the peculiar mutant is a mystery disguised as an enigma wrapped in a conspiracy. Some pinpoint her emergence on the metahuman scene around the Cold War, where she acted as a double agent collecting information for and from both sides. Of course, those are only rumors. What is known is that after a period of silence she has recently reappeared in the Rogue Isles looking for work...
Abilites
Ms. Mimicry has highly adaptive cells that can be altered in a variety of ways, only limited by her imagination and form.
Color Alteration: Her skin and hair can shift into any color in the visible spectrum. This allows her to camouflage herself either into a group of people, by blending her skin and hair to mimic those around her, or into the scenery around her like a chameleon.
Proportion Shifting: While her mutation limitations prohibits her from fully shapeshifting into any form, she has the ability to adjust her body shape, limb proportion, and hair length, to mimic any human being she desires. There are some limitations however, as she cannot shapeshift into anyone too small, as her mass has nowhere to go. Or mimic anyone too big, as she can only stretch out her mass so much (creating inner pockets does alleviate that somewhat, but that has it's own set of issues).
Vocal Mimicry: Alongside her physical changes, Ms. Mimicry can independently alter her vocal cords to directly imitate any sound she has heard before, including inorganic sounds. This has come at a cost, as she has lost the ability to speak in her original voice, and now relies on communicating through copying others.
Body Language Mimicry: Not a direct result of her mutation, but something she has learned alongside it, is the ability to observe, memorize, and copy anyone's specific body language.
Regeneration: Since her cells are in a never-ending state of flux, they are constantly repairing themselves. This keeps Ms. Mimicry from suffering any cellular damage from her mutations, with an added bonus of allowing her to heal from wounds at an accelerated state.