The song features a tape sample of Jack Bruce's voice. Flansburgh explained: "For people not familiar with a Mellotron, it's the first iteration of a sampling device. It's an octave and a half and each note plays its own discreet tape. You know, it's the sound of the flutes in the Beatles' 'Fool On The Hill
' and 'Strawberry Fields Forever
.' It's a familiar sound. Rock stars in the late 1960s all bought Mellotrons and if you were ambitious about it, you could create your own library of sound samples. So on 'I Like Fun,' there's a vocal Mellotron that's a homemade vocal sample created by Jack Bruce of Cream. "
He added: "Jack Bruce made a simple set of sounds of him singing. So when you play a chord you have a choir of yourself playing these notes. The sampler is reanimating Jack Bruce. These sound libraries are all available online. It's super weird. I was going thru these sound libraries and I was like, 'Is this what I think it is? IT IS.' I realize I'm getting lost in the weeds here. But… you actually hear that he uses a glockenspiel as a pitch reference. He hits the tone and sings, 'ahhhhhhhhh.' I like the idea of Jack Bruce at home with a tape recorder and a glockenspiel, singing a scale, cutting up tape and feeding this contraption in his own personal bedroom. That's dedication."