Already been done on a tiny bike.

It must do it entirely by balance on the bicycle seat, the same way a human would. It can't have propellors, reaction wheels, parts in contact with the ground, or other such cheating. It does not need to be humanoid.

It must be able to ride any normal human bicycle; the bike can't be specially designed for it. (It's ok if it fails on a more esoteric design or a bike with broken parts.) It only needs to ride it on a flat surface, but it needs to be able to do so for at least 30 seconds. It must be able to pedal forwards at >10mph.