When a giant's corpse is well-preserved or too fresh to have decomposed away, raising the corpse as an undead will create a giant zombie. Giant zombies act generally the same as zombies of a normal size.

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.