"What Is This" was an American rock band that formed in the early 1980s. The group was known for its fusion of funk and punk rock, characterized by distinctive guitar riffs and rhythmic basslines. Notably, the band's original lineup included future Red Hot Chili Peppers members Hillel Slovak and Jack Irons. Despite their limited commercial success, "What Is This" was significant in launching the careers of its members and influencing the development of the alternative rock genre.