Bebot (V. 1.4, Normalware; $1.99) is one of my favorite apps. It comprises an animated robot that responds to movement on the touchscreen and belts out robotic notes. It's even polyphonic, responding to multiple finger touches at the same time with “harmonized” notes. Amaze yourself and others (although you might annoy them after a while) with this wild app.

FEATURES, AT A GLANCE

Synth controls include Sawtooth, Pulse, Sine and PWM
Effects include Echo, Overdrive and Chorus
Scale Menus contains all of the settings related to playing Bebot in tune as a musical instrument

Find out more information about Bebot.