[Jeff Chandler]

"The druid Finegas catches the Salmon of Knowledge and gives it to him to cook. Finn burns himself while doing so

Grease from the frying pan splashed him?

[RightWhale]

Since you axed . . .

He was ordered to cook the fish without raising a blister on it. Naturally a blister popped up so Fin pushed it back down with his thumb, which got burnt in the process. He chewed off the burn, and kept going through the skin, through the flesh, through the bone, through the marrow of his thumb, at which point he figured out how to dispose of the giant. Smart? You be the judge. But anytime thereafter he needed a shot of wisdom he would knaw his thumb and an idea would come to him.