My child's kindergarten teacher told her kids that she was 100 years old. And therefore since she's older than their parents, she knows more than their parents. (she was younger than me by far) Oh, and she also told them she was a witch and if they misbehaved she'd turn them into a flowerpot - pointing at the flowerpots with flowers in them at her windows.
Of course the children believed every word.
(they also behaved, loved her, and learned a lot from her.)