Knock. Knock.  Trick or treat?   Who are you?   I'm a ghost.  I'm a little ghost.  Knock. Knock. Trick or treat? Who are you? I'm a cowboy.  I'm a little cowboy. Knock. Knock. Trick or treat? Who are you? I'm a witch.   I'm a little witch. Knock. Knock. Trick or treat? Who...