Not a detailed image, but I see Grebes and Snowy Egrets catch these marine creatures regularly. They are always about this size and their defense is to curl into a loop. Both birds have quite a struggle undoing the loop to finally eat it. Anyone know what it is?

Update: It is a Bay Pipefish...a straightened-out Sea Horse relative...thanks Hilary, Glen, and Rusty.

And, thanks to Denise for her correction on the ID of the bird.