Random Robot Percussive Pattern by Sid
Percussive pattern that sort of sounds like R2-D2 dying.
Play with LFO rate to adjust the pattern's speed, and OSC MOD to find a different pattern.
Oh also I just found out that if you change the polarity to negative and put the LFO rate all the way up, it sounds like an old plane. Or an old lawnmower. I thought that was funny. Anyways