There was a monster under Ben's bed.
Ben had known about it for weeks. It wasn't scary. It just hummed.
All night, very quietly: Mmmmm-mm-mm-mmmm.
Ben hung his head over the edge of the bed. "What are you humming?"
The humming stopped. A large, hairy, slightly embarrassed face appeared.
"A song," said the monster.
"What song?"
A pause. "I don't know the name. I made it up."
"Can you hum it again?"
The monster hummed. It was actually quite beautiful — low and rumbly and warm, like the sound of a faraway train.
"That's nice," said Ben.
The monster looked pleased.
"I've been practising," it said.
After that, Ben asked for the song every night.
The monster hummed it, very quietly, until Ben was asleep.
It was the best lullaby he'd ever heard. Even if the monster was a little out of tune.