Fever

Colour changes: heat/harsh light (red), cold/darkness (blue), heightened emotions like excitement/aggression/stress (red), passive (blue*)

*can still control colour change to a degree, so just because it appears calm and blue doesn't mean it's not actively using that to trick prey

Notes: Just a lil guy :) can be depicted with more human tendencies/intelligence for funsies, only marking/details I care about being consistent are the lil heart shaped marking on the neck and cat-like ear/horns on dome - simplify tf out of them as much as you'd like if you wish to draw them LMAO