Who was the monster who almost defeated Zeus?

The monster who almost defeated Zeus was Typhon, a monstrous giant in Greek mythology. Typhon was born of Gaia and Tartarus and was known for his immense size and strength, as well as his ability to breathe fire and produce storms. He challenged the Olympian gods for supremacy, but Zeus ultimately triumphed over him, using his thunderbolts to defeat and imprison Typhon beneath Mount Etna. This battle solidified Zeus's position as the king of the gods.