Conjure Tarrasque

This spell summons a CR 30 Tarrasque, which will go on a destructive rampage. The Tarrasque is controlled by the Dungeon Master.

If the caster desires, they could instead summon a non-Tarrasque creature of CR 29 or below. The caster can choose the creature. This creature would still go on a destructive rampage and be controlled by the Dungeon Master. No CR 30 creatures can be summoned except for the Tarrasque. The creature that will be summoned is chosen at the beginning of the casting time. If no creature is chosen, it will default to Tarrasque.