The mounted combat rules are notoriously poorly written. Here is a humorous example:
Your mount acts on your initiative count as you direct it. You move at its speed, but the mount uses its action to move.
I will continue to use the second person, to keep it consistent with the rule.
On a strict reading of the second sentence, you can use the mount’s action to move. And you can move at the mount’s speed. It says nothing of the mount moving with you, although it does mention that it uses the mounts move action.
A horse in pathfinder moves at 50 feet.
So, the benefits of being mounted in pathfinder is that you gain a move speed of 50 feet. You use the horses action to move. So, the horse stays where it is, and you get to move using it’s movement speed. It’s like the horse catapulted you 50 feet away!
Note that running modifiers are multiplications of base movement speed, and the running feat increases this multipler from 4 to 5. All horses have the running feat. So if you direct the horse to run, you can catapult yourself 250 feet.
Thanks to various errata and addendums, they have added a rule that you don’t get to use a full attack action after a mount moves. “If your mount moves more than 5 feet, you can only make a single melee attack.” But our mount didn’t move. It took a move action, and sprinted, but stayed still. So you can take a full attack action!
To make it even better, you never took a move action. If you move through a threatened square, it is the horse that provokes an attack of opportunity. Even though it is up to 250′ away. I am unaware of any abilities that grant 250′ reach.
So, by being mounted and using what I think of as the horse-catapult feature (It’s a feature, not a bug), you can move 250 feet, without provoking attacks of opportunity, and take a full attack action at the end of the movement. Awesome!
Still, you might think this is kind of stupid. I, however, happen to like Knights. And I want my players to sometimes play as knights, which means they ought to receive a mechanical benefit from being mounted. With that in mind, consider the following argument:
- The rule doesn’t specify that the mount moves when it uses it’s move action. In fact, they specify that the player moves when the mount uses a move action.
- If you only retain your movement speed while mounted, then you need to remain mounted for the whole duration of your movement.
- A 250′ long horse is absurd.
- But mounted combat is clearly intended to be useful for something.
- So clearly the rules are intended to be read as allowing for the horse catapult feature.
Now, you might be inclined to say “but if you aren’t on the horse then you are no longer mounted.” to which I have two responses:
1. They don’t specify you only get the bonuses when riding the mount. Hypothetically, all you need to do is own a horse. A horse is a mount whether it’s being ridden or not.
2. There is no strict definition in the rules for what “mounted” means. As such, it is not clear when the “mounted status” should end.
What if the horse uses it’s move action to move normally? There is no rule saying you go along with it. So, to have a game with knights, I need to either allow:
1. the horse catapult, wherein a mounted knight flies away from the horse.
2. A 250′ long horse.
3. A knight whose horse always runs away from him, leaving him standing alone on the field of battle as his brave stallion charges the orc hordes alone.
The Horse Catapult at Higher Levels
Now, just because it’s funny, keep in mind that if you have enough money you can buy a griffon. It is no longer just like you were catapulted by your mount. You are now soring through the air with a fly speed 80. Let the griffon sprint for 320 feet! And you can fly just 5′ above the ground, so you can go over all the rough terrain, and then just take a short drop that causes no damage.