A fin at Pebble Beach, a light at Lane's Cove, and (don't remember where) a writing slate with integrated compass I had just found! I picked it off the bottom and, for lack of a better place, attached it to the clip on my light and proceeded to swim with the light lanyard on my wrist. Few minutes later I look at my light -- the clip is gone, and so is the newly found slate! The cable tie that used to connect the light and the clip had parted.
I was lucky at that -- had it parted while the light was clipped to a D-ring, I would have lost the light.