Sometimes Spells prevent a target from using hostile Actions, or the spell ends if a creature uses any hostile Actions. A hostile action is one that can harm or damage another creature, whether directly or indirectly, but not one that a creature is unaware could cause harm. For instance, casting Fireball into a crowd would be a hostile action, but opening a door and accidentally freeing a horrible monster wouldn’t be. The GM is the final arbitrator of what is a hostile action.