If a giant's corpse has withered away to little more than bones by the time it is raised as an undead, the giant will be raised as a giant skeleton. Giant skeletons have the same inclinations and behaviors as normal skeletons.

Although most necromancers struggle to apply classical methods for raising the dead to larger corpses, bringing giants back as undead is hardly impossible. More potent spells and more involved rituals can allow a spellcaster to do exceptional things with necromancy, which allows some to animate gigantic corpses the same way as they would humanoid corpses. Other times, giants are raised as undead by other giants, those heretical few who risk exile or death by their community to learn magical arts for the purposes of necromancy. Most undead giants are created unintentionally, however, such as when unholy energies creep into their ancient tombs, often spread by fiends, evil gods, or dark spirits.

Undead Nature. An undead giant doesn't require air, food, drink, or sleep.