The Powell-Thing was a shape-shifting Thing which assumed the forms of Simon Powell and Samuel Holt, sailors from an American fishing boat, the Gettysburg. The creature appeared in the 1993/94 comic series Thing From Another World: Eternal Vows.
Originally part of the Erskine-Thing during the events of the comic-book series The Thing from Another World, the creature broke off from the rest of Erskine-Thing's body and became a fish during its escape from the submarine. The fish was then caught by the American fishing boat, the Gettysburg, and assimilated Powell. Driven by a need to replace dead cells generated by its heightened metabolism, the Powell-Thing attacks and consumes the inhabitants of Wallace Harbour, New Zealand, whilst the vessel is docked there. Notably, the creature consciously avoids infecting its victims with living cells, lest it create competition for itself and draw attention to its activities.
After romancing and infecting Powell's local girlfriend, Jenny Campbell, the local police authorities discover him 'dead' near the docks. Shortly afterwards, Jenny - now the Jenny-Thing - attempts to consume another Gettysburg crew-member, only to discover that he is actually the Powell-Thing, who killed the man and swapped forms. Powell-Thing, face-to-face and as the alien instincts of Jenny's mind, explains to her what has happened and instructs her on how to survive. The following morning, the Powell-Thing (in Holt's form again) arrives at the Gettysburg, but R.J. MacReady and Detective Sergeant Rowan take him into custody and perform a blood test, indicating that "Holt" is a Thing. Powell-Thing then transforms into a monstrous form and tries to kill the two, but MacReady is able to set it alight with a flamethrower. As the Powell-Thing dies, it briefly takes on the shape all those it's previously infected, including Jenny... who MacReady and Rowan immediately realize wasn't a murder victim, and thus is obviously a Thing.