Forbiddance

Ward up to 40,000 square feet of floor space to a height of 30 ft. Teleportation, portals, and planar travel into or through the area are blocked. Choose creature types; chosen creatures that enter or end their turn there take 27 (5d10) radiant or necrotic damage. You may set a password.

This power has its own stable page so it can be linked from any character, item, location, story post, bargain, curse, or future reward.