Genesis, TNG 7
This episode is completely asinine – and yet – I must admit I enjoyed it. Lt. Reg Barclay (jerk!) and his annoying mishigoss somehow causes everyone on board to de-evolve. That picture above is of Troi ribbiting like some sort of frog creature. How they ever got these takes without laughing is a miracle. Worf becomes angry, beastly Worf and…oh…some other crap happens. You should see it for yourself if you are interested.