Fetty Wap -- Named In Assault Investigation (VIDEO)

"Trap Queen" rapper Fetty Wap and his boys jumped a store clerk and beat the hell out of him -- maybe, possibly ... according to the clerk who's got cops hot on Fetty's ass now.

Cops in Paramus, NJ tell us the 19-year-old Shop Rite clerk claims a female patron slapped him Friday night, and then her male friends jumped in and started whupping him in the middle of the store. TMZ obtained this video of the melee.

The clerk told cops he thought one of the male attackers was Fetty Wap, but admits he's not positive it was the rapper because of all the commotion. He only suffered minor injuries and doesn't want to press charges ... but if cops can ID Fetty as one of the suspects, he could still be arrested.