To all the people saying that Lava+Flesh=No more Anikan, let me just say that to explain why Anikan and Obi-wan could be so close to the lava without getting fried and why Anikan latter burns when he is just as close to the lava as he was earlier, George said that Jedi have the ability to use the force that allows them to shield themselves from the heat of the lava, but when Anikan gets his arm and legs cut off he loses control of that power because of his rage, and this causes him to burn because he can't block the lava's heat with force. So if you go by this same logic then when Anikan goes over the water fall he uses this force to shield himself from the lava's heat, but he isn't strong enough to block all the heat so he gets burnt.