What is This Little Squiggly Thing in the Water Off Ferry Beach?

While practicing social distancing, went to the beach and saw something super cool.

If you've never been to Ferry Beach in Scarborough, you are missing a real treat. It's not a typical beach with big pounding waves - it's more of an enclave. You can see Pine Point, Old Orchard Beach and the Black Point Inn area.

It's a curvy beach with a fantastic low tide. The tide goes WAYYYYY out and there are hidden sand bars and great little tide pools. In one of those tide pools, I saw a little squiggly line just sort of going in circles. I thought it was a baby eel. What do you guys think it is?

One thing I noticed is how clear the water is! So pristine. Someone suggested that it's because factories are shut down and pollution is down.

I'm sure that's helping, but probably not the actual cause.

But back to my squiggly line...what is it?