Giant Skeleton

Giant Skeleton
In the Tomb of Horrors, treasure sometimes presents itself for the taking. In one such location, the 'reward' for an attempt to grab some valuables turns out to be the animated skeleton of a giant—deadly not only because of its size and strength, but because it has defenses normally possessed only by undead of much greater power.
Undead Nature
A skeleton doesn't require air, food, drink, or sleep.