A 46
  • You incur an attack of opportunity for entering their square; this is separate from normal movement-generated AoOs.
  • You suffer the squeezing penalties (-4 to attack; -4 to AC; movement costs doubled).
  • You cannot end your turn there. If you try to do so, you're knocked back to the square you entered from.
  • You can’t move through a square occupied by an opponent, unless the opponent is helpless. If the opponent is not helpless, you must exit back the way you came.
  • Your opponent gets an AoO for you exiting their square, as usual for such movement.