There’s a strictly enforced system in Abbott and Costello Meet The Mummy (’55). Old-school mummies kill their victims by strangling them, but whenever Klaris the mummy (Eddie Parker) comes up behind Lou Costello, he can only stand 12 inches behind him with his arms out. When Costello takes a step, Klaris takes a step…but he can’t strangle Costello. He’s only allowed to give him a mummy bear hug. Then again Klaris couldn’t be too toothless. I’m presuming that director Charles Lamont told Parker to make a scary noise every so often. Parker: “What kind of noise?” Lamont: “I don’t know. Some kind of growl.” Parker: “A Wolfman growl?” Lamont: “Of course not. A dead man’s growl..filtered through tana leaves, whatever…the roar of dessicated centuries and ancient pyramids and dry-mouth.” Parker: “Dessicated?” Lamont: “Just don’t sound like the Wolfman.” And so Parker came up with “yaaawwwhrrrrr!”