What did Phaethon ask to do?

He wished to ride his father HeliOS' flaming chariot across the sky.

HeliOS was very reluctant, but finally gave in to his son's demand.

The results were devastating: Phaethon was unable to control

the fiery horses and the chariot caused a panic among the constellations and then came to close to the earth, setting whole lands on fire.

Finally, to prevent even more destruction, Zeus blasted Phaethon

with a thunderbolt.