"After you watch enough Warner Bros. theatrical cartoons it becomes obvious that the directors and animators liked to slip in little hidden gags during the cartoons. The meanings of the gags often would only be understood by a small number of people, or in some cases, the gag was either executed very quickly or was lost in the background. On this website I have captured some of those hidden jokes and gags."

Ah haaaa!! Did ya' ever notice...? Hidden Gags in Looney Tunes and Merrie Melodies Cartoons
Via Drawn!