Shia LaBeouf Goes Berserk on ‘Transformers 3′ Set! (PHOTOS)

Goodness, Shia LaBeouf; that certainly is a terrifying Tyrannosaurus Rex impression you’re doing there!

LaBeouf was ready for action on the Chicago set of Transformers 3 on Saturday, not only busting out a silly expression or two for the entertainment of his co-stars and crew, but rampaging atop a small mountain of urban rubble while wielding a makeshift club of some sort. He even struck a menacing pose toward his co-star Patrick Dempsey at one point, seemingly threatening to rearrange the Grey’s Anatomy hunk’s pretty mug.

Don’t worry, folks; it’s called acting, and it’s why Shia gets the big bucks.

Click through the photo gallery to witness LaBeouf’s on-the-set antics. And make sure to hit up Paparazzi-Razzi for even more pics of your favorite celebs doing amazing things.