Machine Gun Kelly lost it after someone mentioned Eminem. 

The self-proclaimed "Rap Devil" was signing autographs in Los Angeles on Tuesday night, and at first he seemed totally relaxed. But when someone asked "You talk to Eminem since you guys' beef?" he suddenly flipped.

MGK started scribbling out an autograph after that and proceeded to smash whatever he was signing. He then walked away but got into the wrong SUV before he signed an autograph for someone else.

The act comes shortly after Em called MGK a cocks--ker at a recent concert in Australia when someone asked him to perform the  MGK diss record "Killshot." Both rappers got into a heated battle with each other last year after Em accused the Cleveland artist of flirting with his daughter Hailie.

What do you think about MGK getting "big mad"?