Jadeveon Clowney Pranks TMZ Photog ... Laughs In Our Face [VIDEO]

We knew it was coming ... we saw it from a mile away ... but our TMZ photog still fell for one of the oldest tricks in the book last night ... courtesy of Jadeveon Clowney.

The 1st pick in the NFL Draft hit up Mastro's Steakhouse in Beverly Hills with some friends last night ... and though he wasn't talking much, he still felt like screwin' with our guy.

It all started when we tried to talk about the HUGE contract he's about to sign (his friend made it clear he hasn't put the pen to paper yet) ... and that's when the local flower lady stepped into the picture.