FailureThe target is impaled through a leg or another nonvital body part. The creature takes full damage and, if it's standing on solid ground, becomes immobilized. It can attempt to
Escape (the DC is your spell DC). While it remains impaled, it takes damage from any weakness to cold iron it has at the end of each of its turns.
Critical FailureAs failure, but the creature is impaled through a vital organ or its center of mass, taking double damage, and it is
off-guard as long as it's impaled.