 SCP-581 is a horse's nose bag. Any equine subjects, horses, mules, and donkeys have all been confirmed to be susceptible. Zebras, onagers, and other non-domesticated hybrids have not been tested due to budgetary reasons. SCP-581-1's sole motivation appears to be inserting its muzzle within SCP-581. This is strong enough to override instinctual reactions to predator urine, and has caused instances of SCP-581-1 to harm themselves in the process of attempting to free SCP-581 from within steel safes. Only one instance of SCP-581-1 is known to exist at any time.