A character can attempt a bull rush as an attack action made during his or her move action, or as part of a charge. (In general, a character canít make an attack action during a move action; this is an exception.) In either case, the character doesnít get a 5-foot step before, during, or after the bull rush attempt. When the character bull rushes, he or she attempts to push an opponent straight back instead of attacking the opponent. A character can only bull rush an opponent who is one size category larger than the character, the same size, or smaller.
Initiating a Bull Rush
First, the character moves into the targetís square. Moving in this way provokes an attack of opportunity from each foe that threatens the character, probably including the target.
Second, the character and the target make opposed Strength checks. If the character and the target are different sizes, the larger combatant gets a bonus on the Strength check of +4 per difference in size category. The character gets a +2 bonus if he or she was charging. The target gets a +4 stability bonus if he or she has more than two legs or is otherwise exceptionally stable.
Bull Rush Results
If the character beats the targetís Strength check, the character pushes the opponent back 5 feet. The character can push the target back an additional 5 feet for every 5 points by which the character exceeded the targetís check result, provided the character moves with the target. A character canít, however, exceed his or her normal movement for that action. (The target provokes attacks of opportunity if moved. So does the character, if he or she moves with the target. The target and the character do not provoke attacks of opportunity from each other as a result of this movement.)
If the character fails to beat the targetís Strength check, the character moves 5 feet straight back to where the character was before the character moved into the opponents square. If that square is occupied, the character falls prone in the square.