You’re probably too young to remember this (in truth, so are we), but during the run of the original Batman series (1966-68) there was a recurring joke that whenever the caped crusader and his birdy assistant Robin were climbing up a building, someone famous would poke their head out to say high. It was pretty campy, but then again so was the whole show, so why not indulge mental_floss’s 8 Batman Window Cameos, our favorite being Lurch from The Addams Family:

Guzzing!