Primus is the name of a popular rock band. They have been called everything from "thrash funk" to "alternative rock" to "the Freak Brothers set to music." Les Claypool himself once described their music as "psychedelic polka" and a "chicken robot." They are characterized by their unconventional songs and irreverent approach to music - they release their records on Claypool's Prawn Song Records label, a parody of Led Zeppelin's Swan Song, and their catchphrase was - and still is - "Primus Sucks".

While their music is critically lauded, Primus is often maligned for the outward humor of their songs, like Too Many Puppies and John the Fisherman. But their lyrics often have dark undercurrents that belie that humor - Puppies is an anti-war protest, and Fisherman is the true story of a ship going down at sea. Proud of their cult status, once "Tommy the Cat" grew somewhat popular, Primus would introduce songs in concert by saying, "this next song is not called Tommy the Cat." When Wynona's Big Brown Beaver exploded across the national consciousness a few years later they would disown it altogether. Yet despite their vast musical knowledge and endless experimentation, Primus remains largely accessible because of their rock roots.

In their starting days, it was rumored that they used a drum machine, but only for a few months - quickly replaced by then drummer Jay Lane.