It's an electric piano (usually small in size) with knobs on it like a guitar amp has (or garageband... Yes, the app) The knobs can change stuff like the tone and pitch and even volume
@@hollyblocky correct! it's an older instrument that plays samples of instruments with magnetic tapes. i don't fully understand how the actual instrument works, i just found a digital version in garageband. mellotrons have a couple different sounds, which are usually flute, some form of strings, and a choir sound. because of the running tapes, it can have a sort of distorted kind of sound, which is why i like it. some of my favorite examples of the mellotron are any of Spinel's songs in Steven Universe: The Movie, and the chords once the melody comes in in Pigstep.