Trump Shooter Thomas Matthew Crooks Video Shows Him Joking About Penis

Thomas Matthew Crooks -- the shooter who tried and failed to take out Donald Trump -- clearly had a raunchy, sophomoric sense of humor ... as seen in new video obtained by TMZ.

In the clip we got from a former pal of Crooks, you can see him joking about being endowed with 10 inches, and also claiming he's a 6'4" student at Stanford. In reality, Crooks was just a 10th grader when this was shot, and we're told he was making funny videos with classmates while they were all in a computer tech class.

His buddy tells us the video was shot in Feb. 2020 at Steel Center Career and Technical Education in Jefferson Hills, PA -- which provides career and technical education to students attending several public school districts in PA. We have reached out to the school to confirm Crooks' enrollment ... but haven't heard back.

The former classmate says Crooks was quiet at first, but gradually opened up. He was cool, friendly, and got along with his classmates.

Crooks was also described to us as a savant when it came to computer tech. He was one of the most talented students in class -- being able to take computers apart and reassemble them without a hitch.

He was into video games, too, especially "Fortnite" and "Tom Clancy's Rainbow Six Siege." For what it's worth, those are both first-person shooter games.

The former classmate tells us Crooks did not bring up politics or guns while in the classroom. Needless to say, he was absolutely floored to find out Thomas attempted to assassinate Trump.

TMZ got footage of Crooks shooting with an AR-15 style rifle, 130 yards away from Trump after positioning himself on a building just outside the Pennsylvania rally.

As well as wounding the ex-Prez, Crooks killed one person in the crowd and injured 2 others ... before Secret Service snipers killed him less than a minute later.