Here's how it happened:
1. Flattery: The fox, Reynard, praises Chanticleer's beautiful voice and intelligence, making the rooster feel proud.
2. Trickery: Reynard tells Chanticleer about a dream he had where a monster was going to eat him. He then suggests Chanticleer should sing a song so loud that the monster will be frightened away.
3. The Trap: When Chanticleer opens his mouth to sing, the fox grabs him and runs off.
The story teaches a lesson about the dangers of vanity and listening to flatterers.