You can forcefully climb upon a creature 2 sizes larger than you or more within 5 feet of you.

To do so, spend 4 AP, and make an Acrobatics or Athletics check with a DC of 5 + half of the target Creature’s Dexterity attribute score. If the skill check succeeds, you successfully climb upon the creature.

Attacks made against you by the creature you are climbing upon are made with a -3 to Accuracy. However, if you are successfully shoved, knocked, or moved forcefully, you fall off of the creature.

While you are climbing upon a creature, you move using the Climbing rules.