Animation Rig: Cleaner Shrimp
There's nothing terribly unusual about this rig. I used some expressions on the antennae to give them that nice offset motion. I did end up constraining it to the moray eel using a "point-on-poly" constraint in Maya, and then animating the u and v values on the constraint to have him 'walk' around on the surface of the eel's skin. You can see an early test of that concept below.