KT (aka Kids Techno) layers the Japanese electronic toy The Otamatone.
The Otamatone is a singing electronic musical synthesizer toy whose body is shaped like an eighth note with sound emerging from a "mouth" on the notehead. It requires two hands to play: while one hand holds and squeezes the "head", the other hand controls the pitch of the tune by placing the finger on a ribbon controller on the stem; a higher position on the stem creates a lower sound. The ribbon controller is deliberately delinearized to resemble a guitar, so there is a shorter distance between higher notes than between lower ones. Varying the pressure on the head (thereby opening and closing the "mouth" of the Otamatone) creates a wah-wah effect, and shaking the neck (and thereby slightly changing pressure on the head) creates a vibrato effect. Switches on the back of the head allow users to change octave, turn it off or on, or change the volume.