You give a bunch of shellfish to a clown as compensation. The clown did you some favors, and everyone knows clowns only accept shellfish as a form of currency. So your compensation is a pile of random shellfish.
Once the clown has been properly compensated, he looks you in the eyes, one hand full of shellfish, the other in the air, and waves, "Bye (ばい)" he says. "Bye, bye."