This is a machete-shooting slingshot. Or you could call it a crossbow. Just don't call it a catapult or you might wind up with a machete in your gut. From a general standpoint, it's badass, but from a zombie-apocalypse standpoint it's really not that practical because:
1. it's like six-feet long, making it fairly awkward to tote around during an emergency situation (still not sure what I'm gonna do about my penis)
2. load-time takes several seconds, making it a poor choice for fighting off groups and probably only useful for taking out those antisocial "loner" zombies and/or maiming people running faster than you
3. ammo is super-expensive unless
4. you retrieve every machete after a kill in which case that's a whole lot of pulling machetes out of corpses.
Which brings me to my personal weapon of choice: a sword tied to a rope. Here, I'll demonstrate. You just duck a little bit and then swing it around at neck level like so. See? "That's not a sword, that's a Wiffle-Ball bat." OH I'M SORRY, I DIDN'T REALIZE YOU WANTED THE FULL ZOMBIE TREATMENT. "Your mom won't let have a real sword, will she?" Not until the neighbors are all zombies, no.
Video after the jump, actual shooting goes down at 1:37 and 2:30 if you just want to see the action.
Thanks to Chris, who just prepared for the apocalypse by taping two steak-knives to opposite ends of a broomstick. Killer, brah.