"Heathcliff the cat, fucking a midget, with a pigeon's foot in the skyyyyy!"
This particular skill came into play later when Beck and Carl Stephenson, a producer for Rap-A-Lot Records, spontaneously decided to record a song in Stephenson's kitchen. Beck started rapping, and they both got a laugh out of how terrible he sounded. As they were playing it back, Beck just started sarcastically singing, "I'm a loser, baby, so why don't you kill me." Everything else is just random nonsense Beck made up while staring at things in Stephenson's kitchen.
Suddenly the lines about dog food, beef and Cheez Whiz make sense. Well, more sense, anyway.
The track took six and a half hours to record and produce from start to finish. Beck wasn't happy with the song, it being something he slapped together as a demonstration of how bad he was at rapping, and only agreed to release it under pressure from his label at the time, Bong Load. Because who wouldn't recognize the wisdom of every business decision made by an organization with such a name?