Grandad's sitting out on his chair watching as little Johnny grabs a worm and pulls it from its hole in the lawn.
"Well done, Johnny" he says "but I'll give you $5 if you can put it back in the hole". He watches the boy try to poke the worm back in numerous times, and soon falls asleep.
Sometime later, he's woken by Johnny shaking him saying "Look Grandad!". The worm is no longer soft and bendy, but hard and rigid, and the boy easily pushes it back into the ground.
"I say!" says Grandad "How did you do that?" "I sprayed it with Granny's hairspray". "What a good idea. I suppose I'd better get you $5".
Johnny waits as Grandad goes into the house, but he doesn't come back for an hour. When he does, he says "Here's your $5 Johnny. And here's $50 from your Granny as well".