I also have always tied a string to a sponge and when we were in the water I would throw it down to the water and soak the sponge. Then pull it up to help cool necks/butts. I have never had a horse (4 different ones) spook at the sponge, in fact I never even thought about it. UNTIL... Saturday I threw the sponge down and about came off from the spook. The horse thought it must be the creature from the black lagoon coming to get him. Any ideas to get him use to that other than keep throwing it in the water.