To get this weapon you'll need a sword that can break walls. In the Mechanical Pit (Present), go to the room with the fireplace at the top of the pit, where you once fought a Brute. At the back of the room there's a passageway that bends to the right and dead-ends at a water pit. Drop into the pit and you should see a section of wall with light shining through it. Break this wall to expose a weapon rack. Break the rack and you'll be able to pick up the Teddy Bear, an unbreakable secondary weapon that does minimal damage, but restores some health to you every time you hit an enemy with it.