I don't totally know, and I'm not going to research it. But I've been reviewing some of his old stand-up clips tonight and he sure did it a lot. In that light, it's fair to ask about something that has become such a prominent thing these days in pop culture.

Eddie Murphy is typically the one who is credited with starting the mic drop in his Delirious show.

 

I'm with you though, Don Rickles did it many times long before Eddie.