You have learned a little-known trick about teleportation. Whenever a creature within 5 feet of you teleports by means of a teleport spell or similar effect, you can use your reaction to attempt to teleport with the creature even if the creature does not willingly teleport you with it, landing in a 5-foot square next to the creature at the destination if there is room for you to do so. To successfully teleport with a creature in this way, you must succeed on a DC 15 Intelligence (Arcana) check. You are succumbed to all effects the creature you're teleporting with may experience, including mishaps produced from a teleport spell and other effects.
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