Dustin Diamond's getting back into acting in a debaucherous music video filled with sex, drugs, rock and roll ... and murder. He plays Weinstein in rock band TENLo's vid for their song, "Kill All the Things," and, as you'll see ... it doesn't end well for him.

We're told the vid was shot this summer in Milwaukee after band members Joey Zak and TomE LaBrosse reached out to Dustin and he dug it. However, the Weinstein angle was edited in recently ... for obvious reasons.

Actress Kelly Cunningham plays the vengeful nun, and the bandmates play the bellhop and bartender.