Instru-Mental is the backup strip in Teenage Mutant Ninja Turtles: Amazing Adventures issue 13.
The Turtles watch a documentary on a rock band from 1990 called "Glamourshok" and are inspired to start their own rock band. Splinter, however, tells them to find somewhere "many miles away" to start their band.
The Turtles later begin their first session at an old abandoned auto shop. Unfortunately, the locale is close enough to Foot Headquarters that the noise vexes The Shredder. He orders Baxter Stockman to destroy the source of the sound, and he sends Footbots out. The Turtles beat the Footbots, but break their instruments doing so.
The Turtles send a stereo containing their demo tape through the skylight of Foot HQ. Rahzar approaches it and turns it on, but Stockman warns him to destroy it before Shredder hears it. Rahzar complies, but keeps the demo tape for himself.