I'm not just making them jiggle around

And indeed he is not. Alternately fascinating, funny, and creepy, "christhrash's" hobby is reprogramming audioanimatronic robots - which originally were used as entertainment in pizza parlor venues - to do rap performances. The level of work he's put in to get the robot's movements coordinated to the music is amazing. You can find several more of christhrash's videos at his YouTube Space.