Murlong's Shell

Heavy Armor. Grants -2 Defense. The shell is indestructible. Spend 5 XP: Once every Combat, may retract into the shell, becoming invulnerable for 1 round, but unable to do anything else.

Murlong the Wise was a Waedland grand tortoise who lived to be 800 years old, and not just because he was wise. Murlong was also nearly invulnerable.