Season 4, Episode 15: This year’s girl.
Adam, a variation of Frankenstein’s monster (a techno-demon-human-hybrid), brought to life by the demon-fighting secret military organisation “The Initiative”, is killing humans and demons in Sunnydale. “He’s studying biology. Human, demon – whatever he can get his hands on and tear apart”, explains Buffy.
After Buffy and her gang have found one of Adam’s ‘biology experiments’, a disembowled demon, in a tree, Willow characterises their find as Adam “making performance art out of other demons”. This remark has no particular relevance for the story, or for performance art, but it illustrates that, in 1999, such a reference to performance art as a violent cultural practice would make sense in a show that was famous for its pop-culture references.
However, it is interesting to speculate whether the line about performance art factored into the design decisions for the demon corpse and the way it is displayed:
Performance on TV: a growing archive of performance art as it is portayed / represented on television. This might, among other things, be artists making work for or showing their work on TV, it might be people talking about performance art on TV, or it might be fictional performance artists or art appearing in TV series.