Stingray. It has come to my attention that these are more dangerous than I thought. I have a friend who put some fish in his back pocket and went in to feed them. Whilst feeding one in front of him another came from behind and push him over and sucked him to the bottom and held him there. He managed to turn over and the ray released him as he got to his feet it came in again and again it sucked him to the bottom and on the third time he was knocked down he landed with his head above water on the bank.These are like giant suction caps and my friend was lucky to survive. I see some people let children feed them and if this was to happen to a child you would not remove the ray as any attempt to rescue the child would end up with the rescuer being barbed.
Another tie my friend was patting one and as it turned the tail graized his fore heat and opened him up.
On yet another occasion in another location I saw a large man get barbed and it bought him to his knees screaming in pain. Remember being above these you are in the line of fire to there only weapon.