Mr Lancaster thought the cat must have been "run straight over'' as there was no broken skin, but bruising inside, he said.
Interest in the cat had "gone ballistic'' since he listed it as a "great little gift for the mancave''.
More than 10,800 people had viewed it before the auction closed tonight.
Mr Lancaster's typical stuffed possums usually sold for about $70.
He also had some more "unique'' creations in his collection at his Kaimais home - such as a possum-headed chicken with vampire teeth, and a small bird with the head of a child's doll.
The UK-expat said he did not know who bought his works or why but he enjoyed creating them, despite an online backlash which included being called "you sicko'' or being told "hope this happens to you''.
"I just respond with a smiley face.''
Mr Lancaster upset animal lovers when a picture of a doll's face on the body of a possum last year went viral. He said he expected the same this time but was pleasantly surprised at feedback, including comment from an ethical vegetarian referring to the cat as "amazing art''.
Despite the creation, Mr Lancaster said he usually stayed away from working on pets like cats and dogs. "It puts a lot of people's backs up. If someone has known their pet all their life, it's very hard to get it right when you work on them.''
Eliot Pryor, from animal advocacy organisation SAFE, said the sale of the cat was "extremely bad taste''.
"But there is also something distasteful about the attitude shown to an animal once it has died, as the description is light hearted and not respectful.''
