Adynaton is a form of hyperbole (exaggeration for effect). Adynaton takes the exaggeration to an extreme, so that what is being stated is actually impossible.
1. It is raining cats and dogs.
2. It will be 10 billion years before we are finished cleaning up this room.
3. I am so hungry I could eat a horse.
4. My mom is going to kill me when she gets home!
5. Don't look at Mrs. Miller-her evil eye will turn you to stone.
6. When pigs fly...
Examples of Adynaton in Literature
1. "Will all great Neptune's ocean wash this blood clean from my hand?" Macbeth
2. "Feather of lead, bright smoke, cold fire, sick health, still-waking sleep, that is not what it is! This love feel I, that feel no love in this." Romeo and Juliet
3. "It is easier for a camel to go through the eye of a needle than for a rich man to enter the kingdom of God." The Bible