Three Billy Goats Gruff

Three Billy Goats Gruff is a fairy tale first collected by Peter Christen Asbjørnsen and Jørgen Moe in their book Norske Folkeeventyr (Norwegian Folklore) published between 1842 and 1844 in Norway. The story is a eat-me-when-I'm-fatter plot:

Plot
Three goats (often all male—sometimes identified as youngster, father and grandfather, but more frequently said to be brothers. In more modern variations, they are child and parents) have run out of grass to graze on, and must cross a bridge to access a lush meadow where they can eat and get fat to their heart's content!

However, a troll lives under the bridge, and eats anyone who tries to cross his stream. The smallest goat steps up to the bridge first, and the troll jumps up on the bridge and threatens to "gobble him up"! The small goat convinces him to not eat him, as he is only small, and he could eat one of the bigger goats instead! The troll agrees, and a larger goat begins to cross the bridge:

Again, the troll prevents further progression and threatens to eat the middle-sized goat. The goat tells him not to eat him/her, as that would mean he wouldn't get to eat the biggest goat, and the troll agrees.

The biggest goat crosses the bridge, and when the troll jumps up in front of him, he barges the troll out of the way into the stream with ease! The three goats enjoy eating the grass in the meadow, and the troll never bothers anyone again.