Is there any way in Pathfinder to end your movement in another creatures space? Let's ignore the special exemptions for creatures of greatly different sizes.
The rules contain the rather absolute statement that
You can't end your movement in the same square as another creature unless it is helpless.
They further clarify that
Sometimes a character ends its movement while moving through a space where it's not allowed to stop. When that happens, put your miniature in the last legal position you occupied, or the closest legal position, if there's a legal position that's closer.
I could have sworn that in 3.5 there were rules that, if you were forced to end movement in another creatures space, you would end up prone. And I can at least imagine a scenario where the above rules break down -- tumbling through a line of several enemies and then being tripped by an AoO, for instance. There are even (contrived) scenarios where there might be no legal place to move, such as barriers being activated on readied actions.
Is there something I'm missing in the PF rules, or are they as absolute as they seem?
edit: Here's a slightly more amusing example: cast reduce person on a halfling, cast enlarge person on a human -- now they can move into the same space due to the size exemptions. Dismiss the spells. :)
However, I'm now assuming that KRyan is right here, and there simply are no rules. I looked all over the place for the "forced prone" thing I thought I remembered from 3.5, and I think it must just have been a house rule. (Although one I will continue to use, since it makes more sense to me.)