We've some strange suspensions over the years, but this one might be the strangest of them all.

Owen Tippett, who plays for the Mississauga Steelheads, was reportedly suspended for one game for flicking a foam puck that was thrown onto the ice over the boards.

Apparently putting a puck into the stands is usually a 5-game suspension, but because it was a foam puck, they reduced it to one game.
We didn't know this was a rule, but apparently it's being enforced quite a bit lately.
(H/T: /r/hockey)