Trip and AoO Moving

[Red_Death01]

now I can understand you can trade an AoO to make a trip instead but, how does this work when your opponent moves out of a threatened square and you respond by tripping them? Do they move 5 ft away as they fall face first running away or do you "in essence" cancel out their move and they fall prone?

[tyckspoon]

You cancel their move; an AoO pre-empts the action that triggered it, so your trip happens while they are still in their original square.

[Red_Death01]

Alright thanks! I figured as much but I couldnt find a reference to this. Thought someone would know the answer easily enough :P

[DeltaEmil]

If the enemy provokes an AoO from you because of the movement, and you trip them, they must crawl, having only a speed of 5'. The trip comes before the movement, so the enemy first provokes an AoO, you trip the enemy in response (assuming you do not provoke AoO yourself by doing so), the enemy becomes prone, and can now choose to either crawl 5' away, or stand up, provoking another AoO in both cases.