OK, to beat him, make ellie suck water, u do this by holding down the and pressing "R", ellie would stop sucking water by herself, to release the water that ellie suck u pres "R", the purpose is to hit the snail eyes. So jump and press "R". I know most ppl thik is that pressing "B" is the correct way, well is not, "B" is to be pressed when there is a barrel u can reach, u press it and ellies trunk will suck the barrel to her.