Dweomormir’s Dimensional Anchor

You lash a creature’s fate to the current plane. When a creature within range attempts to teleport or plane shift, you can cast this spell as a reaction. The triggering effect automatically fails with no saving throw, and the slot/charge/ability used for that effect is not expended. While you maintain concentration for up to 5 rounds (30 seconds), the target cannot teleport or plane shift by any means.

If your concentration remains unbroken for the full 5 rounds, the creature becomes anchored for 24 hours: it cannot teleport or plane shift for the duration.

This spell doesn’t otherwise restrain the target’s movement, and it doesn’t dispel ongoing effects unless they would move the target via teleportation or planar transition.

Notes (DM).

• Range only matters at the instant of casting. Afterward, the ongoing concentration doesn’t require the target to stay within 90 feet.
• “Teleport or plane shift” includes features such as misty step, dimension door, teleport, plane shift, word of recall, and innate/champion abilities that explicitly say teleport or shift planes.
• The reaction negation clause is unusual by design: the blocked effect is not spent; the target could try again on a later turn if they find a way to break your concentration.

“Doors shut. Windows barred. You’re here—with me.” -Dweomormir Slate