Gate Locks are bosses from Final Fantasy X. During the battle against Evrae Altana, the party can choose to fight or to use Trigger Commands to break these locks in order to escape.
Even though Gate Locks are immune to all elemental and magical damage, this is irrelevant under normal circumstances. The only means of interaction is through the Open lock trigger command, which is a physical attack that completely ignores the user's weapon properties. Despite only dealing fixed 50 HP damage, each lock will open with a single hit.