Other distinguishing features: Proteus exists in a
pure energy form, although he could take possession of
humanoid bodies.
Strength level: Proteus exists in a state of pure psionic energy and hence has no physical powers. When he inhabits a host body he possesses whatever physical strength that body possesses, although his energies rapidly "burn out" the body, weakening him until he can take possession of a new host.
Known superhuman powers: Proteus is a mutant who
possesses the vast psionic ability to manipulate and alter
reality. Originally Proteus could not use his reality
warping powers against another person unless he made
visual contact with his victim. However, he apparently
did not suffer from this limitation with regard to inanimate
objects, since he was able to extend a "reality warp"
over much or the entire city of Edinburgh.
Proteus also possesses telepathic abilities. Some of
the X-Men have theorized in the past that Proteus
merely creates illusions in people's minds that he
manipulates reality, but the preponderance of evidence is
that Proteus's reality-warping powers are indeed real.
After Proteus's powers "burned out" his original body,
he existed in a state of pure psionic energy. He could
take possession of a human body as a host, but his
energies rapidly "burned out" the body, killing it. His
energy form would rapidly disperse unless he took
possession of a new host. Proteus' energy form could
also be dispersed by metal, even when he occupied a
host body. He was also vulnerable to organic metal such
as Colossus' body. Dr. MacTaggert once kept Proteus
imprisoned within a metal cell, but it has not been
explained why Proteus did not simply use his
reality-warping powers against her to escape; perhaps
the cell's special energy fields somehow prevented him
from escaping.
After Proteus and Piecemeal merged, the resulting
energy being was no longer vulnerable to metal.
Moreover, the amalgamated being apparently no longer
needed host bodies in order to survive, nor did it have to
see a living victim in order to use his reality-warping
powers upon him.