As far as homemade weapons go, they don't get much more dangerous or crazy than this machete-shooting slingshot. Your potato cannon just got seriously one-upped.
For some reason, this guy made a weird crossbow/slingshot hybrid designed to launch a machete at a very high rate at the target of your choice. It looks incredibly dangerous! If that rubber band snaps, it seems likely that the machete would come back and hit you in the face, which is the last place you want a machete to hit you. But hey, in terms of keeping the neighborhood kids terrified to come near your property, this will do the job quite nicely.