Ah, the innocence of children. So free of corruption and cynicism, so sweet and sincere. Laughing and playing and introducing supremely destructive monster snails to Florida, where the beasts eat almost anything that’s green and then crap all over houses — quite literally laying waste to whole neighborhoods.

This actually happened in the 1960s, when a boy vacationing with his family in Hawaii had pocketed a few giant African land snails (Lissachatina fulica), a mollusk that grows to a foot long and a full pound. Hawaii had been battling the pest, and so too would Florida, where the boy returned with his new friends. Once home, he quickly grew bored of the snails and handed them over to his grandmother, who set them free in her backyard.

What ensued was an invasion by rapidly reproducing critters that have over the last century spread out of their native East Africa into tropical climes all over the world, from Asia to South America, as stowaways on ships or as pets brought home by people with a thing for snails. In Florida, eradication took seven years. Other places, like Brazil, have not been so lucky in their efforts.

You see, the giant African land snail is a hermaphroditic love machine. “Snails have female bits and male bits,” explained biologist Robert Cowie of the University of Hawaii, “a single pore, through which if you’re acting as a male, a penis extrudes, or if you’re acting as a female, through which the other snail puts its penis in. And in some cases they can do it reciprocally.”

Thus the giant snail never meets another snail it can’t get busy with. Once fertilized, the snail will bury several hundred eggs a few inches below ground, and because of the incredible size of the species, the young will emerge far larger than native varieties, making them that much more resistant to predation.