No form of attack can suppress the tarrasque's regeneration-it regenerates even if disintegrated or slain by a death effect. If the tarrasque fails a save against an effect that would kill it instantly, it rises from death 3 rounds later with 1 hit point if no further damage is inflicted upon its remains. It can be banished or otherwise transported as a means to save a region, but the method to truly kill it has yet to be discovered.