He thought the shower was empty, but when he pulls back the curtain? Surprise!

The gang at Just For Laughs: Gags have been pranking the unsuspecting people of Montreal and Vancouver for as long as I can remember.

It's hard to pick my favorite prank, but this one definitely makes the top ten.

The pranksters approach people in the mall, asking for assistance with a shower curtain installation. The people think the shower is empty, but when they pull back the curtain? Surprise!

Watch video below.