Jawzahr

According to the book Dragons: Fearsome monsters from myth and fiction:

'''In ancient Persia, eclipses occur when Jawzahr the comet dragon swallows the Sun or Moon. He menaces the two great luminaries, chasing them around the sky and devouring them at regular intervals. Jawzahr commands a legion of demons and is a crafty, curious dragon. He disguises himself as a god one day and drinks an immortality-giving potion meant only for the gods. The Sun and Moon, however, see everything and they report Jawzahr's trickery to the gods. As punishment, Jawzahr's head is severed with one well aimed throw of a discus. But Jawzahr is already immortal because of the potion he drank and cannot be killed. Enraged, Jawzahr ascends to the sky. The two immortal parts of him live on separate from each other. Jawzahr is angry at both the Sun and Moon for revealing his deception to the gods. He forever chases the Sun and Moon, gobbling them down when he catches them. Any time an eclipse occurs, it means that Jawzahr has caught up with and consumed the Sun or the Moon. As for his tail, it emits a shower of comets that stream across the night sky.'''

A dragon from Islamic mythology, Jawzahr first made his appearance in legends from Persia, which is modern-day Iran.