Mystery Blob seen while kayaking in Chincoteague Bay

Not even the park naturalists had a clue. (there was a thought it might be a fragment of something larger). It was hand sized, and drifting at the edge of the salt marsh. We were in a shallow, warm bay (eelgrass beds, oyster shoals) where a lot of things drift or swim in from the open Atlantic. The common jellies here are moonjellies and sea nettles and coomb jellies. Love to know what it is.