The Stand-in - S1-E9
Revealing mistake: When Pufnstuf tries to reason with Witchiepoo, Witchiepoo hits him with a giant powder thing and shouts "Make up." When Pufnstuf falls over his head almost disconnects to his body.
Revealing mistake: When Cling and Clang hit Witchiepoo and see flies in the air and falls, the wire lifting her up is visible.
Revealing mistake: In the song "Living Island", we see Judy frog jumping over Pufnstuf. When she goes back down, the wires holding her up and putting her down are visible.
