A man obtains knowledge of animal languages but if he reveals the secret, he must die. Once he hears animals talking and laughs. His wife thinks that he laughs at her or at her mother. The man is ready to open his secret and either does it and dies or hears how animals (usually a cock) blame him for being so foolish. So he keeps his secret.
Person believes that unachievable natural phenomena are objects of culture. Usually he agrees to bring a the fire mistaking for it a sunset, a firefly, etc.
An ogre or a stronger animal catches a man or a weaker animal or drives him into a small enclosure. He goes away for a while leaving a watchman. The watchman is unable to fulfill his duty and the man (the weak animal) escapes (usually he dupes the watchman). Most, though hardly all American cases can have post-Columbian African origin
A weak person's demand will be granted if he brings a skin (paw, tears, etc.) of animals stronger than he. He fulfills the task using tricks (but usually does not receive the promised reward)
Person invites others to help him in his work. Every next one is stronger than the one who came before and eats him up, the last two perish when they begin to fight