Blackfoot Lodge Tales, by George Bird Grinnell, [1892], at sacred-texts.com
Once Old Man was travelling, and becoming tired he sat down on a rock to rest. After a while he started to go on, and because the sun was hot he threw his robe over the rock, saying: "Here, I give you my robe, because you are poor and have let me rest on you. Always keep it."
He had not gone very far, when it began to rain, and meeting a coyote he said: "Little brother, run back to that rock, and ask him to lend me his robe. We will cover ourselves with it and keep dry." So the coyote ran back to the rock, but returned without the robe. "Where is the robe?" asked Old Man. "Sai-yah!" replied the coyote. "The rock said you gave him the robe, and he was going to keep it."
Then Old Man was very angry, and went back to the rock and jerked the robe off it, saying: "I only wanted to borrow this robe until the rain was over, but now that you have acted so mean about it, I will keep it. You don't need a robe anyhow. You have been out in the rain and snow all your life, and it will not hurt you to live so always."
With the coyote he went off into a coulée, and sat down. The rain was falling, and they covered themselves with the robe and were very comfortable. Pretty soon they heard a loud noise, and Old Man told the coyote to go up on the hill and see what it was. Soon he came running back, saying, "Run! run! the big rock is coming"; and they both ran away as fast as they could. The coyote tried to crawl into a badger hole, but it was too small for him and he stuck
fast, and before he could get out, the rock rolled over him and crushed his hind parts. Old Man was scared, and as he ran he threw off his robe and what clothes he could, so that he might run faster. The rock kept gaining on him all the time.
Not far off was a band of buffalo bulls, and Old Man cried out to them, saying, "Oh my brothers, help me, help me. Stop that rock." The bulls ran and tried to stop it, but it crushed their heads. Some deer and antelope tried to help Old Man, but they were killed, too. A lot of rattlesnakes formed themselves into a lariat, and tried to catch it; but those at the noose end were all cut to pieces. The rock was now close to Old Man, so close that it began to hit his heels; and he was about to give up, when he saw a flock of bull bats circling over his head. "Oh my little brothers," he cried, "help me. I am almost dead." Then the bull bats flew down, one after another, against the rock; and every time one of them hit it he chipped off a piece, and at last one hit it fair in the middle and broke it into two pieces.
Then Old Man was very glad. He went to where there was a nest of bull bats, and made the young ones' mouths very wide and pinched off their bills, to make them pretty and queer looking. That is the reason they look so to-day.