Bill the Cat, or Bill D. Cat, is a fictional cat appearing in the works of cartoonist Berkeley Breathed, beginning with the comic strip Bloom County in the 1980s and continuing in Outland, Opus and a Facebook revival of Bloom County in the following decades. In the original strip and revival, an accident with a boat anchor results in Bill becoming host to Donald Trump's brain.
When Hammer takes Peter to Coachella in "HTTPete", he notes that Neil Young is on a side stage asleep in front of a television. Peter admits confusing him for Bloom County's Bill the Cat.