halberd, poleax

I could see adding a special move for "pull rider down" or some such for a poleax
Opposed resolution, no damage except when the knight hits the ground
and yes, it would modify the rider's roll to stay on

I could see this being used, if my players would ever consider that weapons do more than go "smackity smack."

Great Idea. Things like this fit well into my playstyle.