Whale Sharks - Isla Mujeres, Mexico
These guys come straight at you mouth wide open. Basically, they're gentle and harmless creatures, so we're both in "do no harm" mode. When they're 3-4 feet away, I go off to one side and they go past. Yesterday, I zigged off to my right and the whale shark went the same direction and we had a minor collision. I pushed off the top of his head, my back brushed the side of his dorsal fin and he whacked me slightly with his tail. No harm done.