A grizzly bear livened up proceedings at a Minnesota Zoo on Monday – by grabbing a rock and repeatedly smashing it into the glass wall of its enclosure.
The bear – armed with its basketball-sized rock – startled visitors on the other side of the five-layered pane, though no one was hurt.
Zoo animal collections manager Tony Fisher told the Minneapolis Star Tribune the glass stayed in place "like a windshield."
The grizzlies have been relocated to their indoor pens and the area will be closed until a new pane of glass has been installed.
Fisher isn't sure which of the three bears is responsible for busting one of pane's five layers.
But he suspects it was Kenai, a nearly full-grown male who is "usually the clown out there."