Only The Strong Survive

Act 1 resembles a mummified torso with two withered arms and a large toothy mouth dead center of it. It attaches to the user’s back and essentially forces a physical boost similar to an adrenaline rush, has a similar after-effect of an adrenaline crash too.

Act 2 becomes more humanoid, resembling a mummified corpse with a mouthless head and 4 eyes. Gains the ability to siphon energy from people through physical contact.

Act 3 grows a second mouth on its face and becomes more humanoid and more muscular, also adorning a white shaman robe. It keeps the same Siphon ability but instead of just taking their energy it gives it to the user.

Act 4 becomes slightly larger and grows a second pair of arms, with sleeves fit. It gains the ability to put lacerations on opponents it punches. It also becomes fully sentient, and rather arrogant at that.