A friend in Windhoek gave me mine, Andre. I first saw these many years ago in Lusaka, Zambia, used by the posties on their delivery bikes -- they used their catapaults to make sure that the dogs in the wealthier suburbs kept their distance. Their catapaults used cut-up recycled bike tires.
Not many things will make a raccoon retreat, but a couple of summers ago I used my catapault to chase one from a tree near our back deck and BBQ -- he was eyeing our meal. Just a small stone on the rump was enough. He was a big guy, and thoroughly indignant about the indignity visited upon him. Doubt I'm a good enough shot, though, to hit a squirrel as Julian did.