Yoppa (Yopper) is a slang term which is used to refer to ecstasy and automatic weapons.
Yoppa(s) is often used to refer to ecstasy pills (MDMA). In Lil Herb's I'm Rollin song, he raps, "Hit the club deep and we off them yoppas. - All my n*ggas fly, we came for the b*tches."
Yoppa is used by numerous rappers in their rap songs to refer to choppas (automatic weapons).