Phoenix Egg

May not be valid outside the same "Monsterverse" DC series
Characters have obtained a phoenix egg. It is immune to all damage and will grow into a tiny phoenix chick non-combatant pet. Characters can expend 10 downtime each time to turn the chick into a young adult phoenix mount temporarily for one hour. The phoenix can only be used as a mount in any adventure. Those mounted on the phoenix are not harmed by its flames while riding on the mount.