Pittsburgh Football Players Scared Crapless By Hilarious Halloween Prank

Wanna see grown-ass college football players cower in fear over a harmless Halloween prank??

Good ... 'cause University of Pittsburgh football staffers scared the crap out of their team with a fake mannequin -- and the video of the players' reactions is HILARIOUS!!

The team's assistant director of player personnel, Karlo Zovko, pretended he was a dummy wearing a Pitt uniform ... and when guys walked by, he pounced.

Ya gotta watch the video ... some of the players hit the deck, some screamed out in fear -- and one of the dudes even threatened to punch Zovko in the face!!!

Pitt head coach Pat Narduzzi clearly loved watching it all ... he tweeted out the vid, writing, "Halloween Night, don't get tricked! Hail to Pitt!"