One touches the ground and it begins to tremble, after 12 seconds the entire ground shatters as far as the caster can see, the ground is transformed into extra difficult terrain, any creature within that area must make a Constitution saving throw. If a creature (large or smaller) fails a Constitution saving throw they are knocked to their knees and then restrained with a strength dc of 20 to escape. Any creature takes 12d8 thunder damage and 6d8 force damage or half as much on a successful saving throw.