Yet another of life's big mysteries. This one has kept me awake at night too. Can a worm tie itself in a knot?
I found this earthworm yesterday at the nature center in a cup of night crawlers, so the answer is: yes. But why?
Here's the best Internet answer, and it's not the yoga position called the slimy pretzel. "They do this when the soil gets too dry or cold, it
cuts down on water and heat loss. But as they have a slimy coat they are
able to uncurl themselves."
Looks like an overhand knot to me.