[RPG] Does The Amazing Lightspeed Horse work, RAW

actionsdnd-5emountoptimization

N Medium humanoids have gathered on an arbitrarily long field, standing in a line with each creature 120 feet away from each of its neighbors. The creature at one end of the line is mounted on a horse with a speed of 60. The creatures are arranged in initiative order, such that all N creatures will act in the order of their position in a single melee round. The mounted creature acts first.

Each creature other than the mounted creature is holding a pike and has readied an action to Shove the next mounted creature that moves adjacent to it.

On its turn, the mounted creature commands its mount to move 60 feet towards the next creature, then drops prone (which is not stated as a condition for dismounting in the Mounted Combat section of the 5e PHB) and orders the horse to Dash and move 60 feet more, closing the distance. At this time, the next creature's readied Shove triggers, and it makes an attack on the rider. Assuming the attack hits (which is likely, given that the rider is prone, thus granting advantage, and for the sake of the example has no armor or dexterity bonus to AC) the rider will be pushed off of his mount and the mount leaves his control. At this time he has used his actions and the second creature's turn begins.

Creature 2 starts by mounting the now-adjacent horse, whose initiative changes to match his. However, the horse's turn ended when its first rider's turn did, and thus it is taking a new turn when its second rider mounts it. The second rider orders it to move 60 feet towards the third creature, drops prone, and orders it to Dash another 60 feet, triggering the third creature's readied Shove. This procedure continues until one of the Shove attacks fails, allowing the horse to move a theoretically infinite distance in a single 6-second round.

I am absolutely certain there is a flaw in this logic, but I can't find it – what error breaks this strategy?

Best Answer

No. The Amazing Light Speed Horse™ cannot move an infinite distance

(And what distance it does move without taking the dash action is at a speed of at most movement per round, and with the dash action is 2×movement per round.)

Per the definition of movement from the Basic Rules v 0.3, page 63, and also from the Player's Handbook, page 181:

Every character and monster has a speed, which is the distance in feet that the character or monster can walk in 1 round.

(Note that the riding horse is stated as a monster in the Player's Handbook on page 310, and the warhorse on page 311.)

Your exploit only works if you incorrectly substitute turn for round under an assumption along the lines of somehow the horse receives one turn for each humanoid rider's turn, rather than one turn per round. While the second individual could attempt to mount the horse on their turn in your scenario, the horse will already have used all its movement for the round.