Carry a beaver

There's a guy who's hiking in the woods one day when a bear chases him up a really tall tree. The bear started to climb the tree, so the guy climbed up higher.

Then, the bear climbed down and went away. So the guy starts to climb down the tree.

Suddenly, the bear returns, and this time he's brought an even bigger bear with him. The two bears climb up the tree, the bigger bear going higher than the first. But the guy climbed even higher still, so the bears couldn't reach him.

Eventually, the bears went away. Naturally quite relieved, the guy starts down the tree again. Suddenly, the two bears return. But this time the guy knew he was in big trouble. Each bear was carrying a BEAVER.