Magic Circle
3rd-level Abjuration · XPHB, p. 293
Description
You create a 10-foot-radius, 20-foot-tall Cylinder [Area of Effect] of magical energy centered on a point on the ground that you can see within range. Glowing runes appear wherever the Cylinder [Area of Effect] intersects with the floor or other surface. Choose one or more of the following types of creatures: Celestials, Elementals, Fey, Fiends, or Undead. The circle affects a creature of the chosen type in the following ways: The creature can't willingly enter the Cylinder [Area of Effect] by nonmagical means. If the creature tries to use teleportation or interplanar travel to do so, it must first succeed on a Charisma saving throw. The creature has Disadvantage on attack rolls against targets within the Cylinder [Area of Effect]. Targets within the Cylinder [Area of Effect] can't be possessed by or gain the Charmed or Frightened condition from the creature. Each time you cast this spell, you can cause its magic to operate in the reverse direction, preventing a creature of the specified type from leaving the Cylinder [Area of Effect] and protecting targets outside it.