Lyxen
Great Old One
Something else that you might use is maybe the Spirit gives to the player enchanted feathers (Quaal Feather Token) that give them a one-use Feather Fall effect (and it might even fade in a few days if you don't want the players holding onto them for later), so that the aim can still be "ride the roc for as long as you can to impress the spirit", but if a player fails, it does not mean instant death.