The Ark of The Covenant is a weapon created by God. Sam claimed to have found it while praying to Castiel to get his attention, and Cas actually shows up, indicating that it's probably an actual weapon. It's powers, and uses, however, are unknown.
- In lore it was often a means used by people to communicate with God.
- The Ark was made most famous by the movie Raiders of the Lost Ark which Sam refers to when luring Castiel to him.