The world is a little more quiet today because Ron Palillo passed away at the age of 63 from a heart attack according to WPTV and there is no one to scream out Oo Oo Oo Oo Mr Kotter the way he did. Palillo is best known for playing Arnold Horshack on the ’70s sitcom Welcome Back, Kotter, the little guy with a huge heart. So today remember him with a smile as big as the one he gave us with all of his projects and watch him in the show that made him a household name.