AKA how I learned to stop worrying and kill the mount.
So to get on to my actual question, what happens when a mount is killed in the middle of the rider's charge? Via reach AoO, or a ready action. It goes without saying that the charge is invalidated, as they can no longer reach you (making you an illegal target). My question is, what actually happens to the rider?
My guess is they have to take a ride check for falling off the horse, to avoid damage and falling prone, but is there any RAW stipulation for what happens? I'd also like to think that the added momentum from the charge causes them to fly off the mount for added effect, but I'm really just speculating.