Meraxes, The Omniscient

Flying
{b}{t}: Target opponent reveals the top seven
cards of their library. You may cast up to 3
instant or sorcery cards from among them
without paying their mana cost. Then that
player puts the rest in their graveyard.

It wasn't just Aegon riding his dragon, it was
Rhaenys and Visenya, too...Rhaenys rode
Meraxes.