Role-playing Games Stack Exchange is a question and answer site for gamemasters and players of tabletop, paper-and-pencil role-playing games. It only takes a minute to sign up.
Sign up to join this community
The thorn whip cantrip description is:
You create a long, vine-like whip covered in thorns that lashes out at your command toward a creature in range. Make a melee spell attack against the target. If the attack hits, the creature takes 1d6 piercing damage, and if the creature is Large or smaller, you pull the creature up to 10 feet closer to you.
If the cantrip is directed to a target riding a mount and hits, should both mount and rider be pulled?
There is nothing in the mounted combat rules (PHB 198) that would impose special rules on forcibly moving mounted creatures. The target will be moved away from their mount and thus would cease to be mounted.
At my table I would rule that this would count as dismounting the rider and thus any feature that prevents you from being dismounted (like the Saddle of the Cavalier) would negate the forced movement.
