You know what's worse than a rat scurrying in front of you when you're walking home from the train late at night? Going to take out your garbage and running into an angry, hissing possum.

Sadly, this is not what was on the mind of New York City officials when they thought they'd try their hand at biological control a few years ago. Their solution to our rat problem? Introduce possums into the city.

Apparently they thought the possums would die out after they killed all the rats. What they did not realize was: possums will eat just about anything and are capable of reproducing. Oh, also they have like 50 teeth, smell terrible and are generally terrifying.

Now there are passels of possums roaming the boroughs at night. Good plan, guys. Maybe we should just release some bobcats to deal with the possums now, no?

Sadly, this possum debacle isn't the first time man's attempts at fighting nature with nature have gone horribly wrong. More tales of misguided science after the jump.

Cane Toads in Australia
The sugar crops of Australia were under attack by beetles. Someone who had just attended a conference had a brilliant idea: "I know, let's let loose a box full of exotic poisonous toads. That should solve our problem!" Uh, it didn't. The toads couldn't jump high enough to kill the beetles, instead eating everything else within range. Their numbers have since grown so high -- from the initial 102 brought to the island -- that there are now toad-hunting days. Further, scientists have invented a special "cane toad sausage" to try to teach endangered species not to eat the toad meat, because it is poisonous. Now the research community is focusing on genetic experiments to solve the problem -- because performing genetic experiments on a poisonous toad doesn't sound like the beginning of a 1950s horror film or anything.

Mongooses of Hawaii
In yet another failed bid to protect sugar crops, this time from rats, a Jamaican farmer got it into his head that mongooses would solve his problem. He believed in his insight so strongly that he sailed across the ocean to Calcutta, India, to bring back five of the little guys. He later wrote of the mongooses' success, turning the animal into a brand-new Jamaican export. More than 70 of the critters were ordered and have since taken over all but two of the Hawaiian islands. Locals have been quite sad to learn that, much like possums, mongooses don't live on a strict rat-only diet -- they'll eat anything and love eggs, so don't expect to see too many birds on your honeymoon unless you stay on mongoose-free Lana'i or Kaua'i. "Why mongooses? Why not cats?" you may be asking. Well, they tried that. It didn't work out too well either.

Feral Cats in Antarctica
This one's a doozy. In the early 19th century, the seals and penguins of Macquarie Island attracted many hunters -- and with the ships that brought the hunters came rats and mice. So, cats were brought in to handle the rats. Then, 60 years later, somebody left behind some rabbits for other sailors to eat. The cats ate the rabbits, but not enough of them; the rest were thinned out with a bunny-offing virus. Without enough rabbits for the cats, the felines started eating the island's native burrowing birds. Locals didn't like that, so all the kitties were shot. And now, without any cats left, there are an estimated 100,000 rabbits roaming the island, eating all the plants and making the island's Royal penguins -- who breed there -- more vulnerable to predation. It will cost an estimated $17 million to get rid of all the rabbits. Might we recommend some cats?

Ladybugs Across America
Apparently not pleased with the work our ladybugs were doing to rid crops of aphids, American farmers turned to Asian lady beetles and the seven-spotted ladybug. Unfortunately they spread like wildfire across the country, so much so that now the state insect of New York, the nine-spotted ladybug, is locally extinct. We know. We're breaking your heart. But here's where it gets serious: The ladybugs are doing so well and have taken over so much of the country that they are now affecting our wine supply. A chemical from the bugs that's meant to protect against predators is so potent that it can easily disrupt the taste of your wine. Oh, and it's called "ladybug taint," as in, "You just drank some ladybug taint." Thanks for that one, science.