Why the Possum Plays Dead: Rabbit and Possum both want wives, and Rabbit is faster than Possum. Rabbit leaves Possum in the dust for the village they plan to find wives at, and tells everyone that they must pair up immediately. When slow Possum finally arrives he has no options, so he decides to try his luck at the next village, but Rabbit is mean and tells the next village that they must have war. When Possum arrives he is beat up by the other animals, so to save his life he plays dead. This is why Possums play dead.
How the Deer Got His Horns: This Cherokee tale warns of the repercussions of cheating. Deer and Rabbit want to decide who is faster, and the prize will be a nice set of antlers. All the animals gather to officiate the race. Before it can begin, Rabbit wants to check the thicket they will be running through since he is unfamiliar with the country. The other animals find him cutting a path through the thicket for himself, so they declare Deer the winner by default. This is why Deer has antlers.
The Spirit Land: In this story, crow is the intermediary between the living and the dead. Crow creates the bridge for the people of the spirit world to interact with the living people of the sunrise land. Crow does this by dropping a seed, which spurts into a huge mountain which the spirit people can descend. Crow then drops dust, grass, and twigs which correspond with the creation of land, prairie, and forest. Crow now lives on the western edge of the world.
image source Deer and Rabbit
bibliography source Myth-Folklore Unit: Great Plains