There's not much to add to this AP story: "Pot-firing catapult found at Arizona-Mexico border". It's a catapult. It fires pot. National Guard troops spied on drug smugglers using it to shoot marijuana over the border, then seized it.
Here's a spy video of the pot being catapulted by smugglers, taken on Friday evening. And here's another picture of the weed catapult; this time it looks like the national guard troops are trying it out:
In other news, Wile E. Coyote is apparently Mexico's newest drug lord.