Cats! They’re beloved pets, the internet’s favorite sources of content, and truly horrifying killing machines. Sure, the little hunters massacre tens of billions of birds and small mammals every year, but even when they’re not trying, cats can kill — thanks to a deadly mind-controlling zombie parasite that only grows inside kitty guts.

A recent story in Outside Magazine highlighted the destruction that legions of feral cats and their Walking Dead poo are wreaking on native Hawaiian wildlife. Cats, you see, are an integral part of the parasite Toxoplasma gondii’s life span. Toxo, as it’s known, can only reproduce inside a cat — no other animal will do. It then spreads via feline feces.

If a rat comes into contact with any of the millions of microscopic oocysts the cat crapped out, it becomes infected. And — here’s the really messed up part — T. gondii takes over the infected rodent’s brain and overrides its innate fear of cats. The zombified rat is then more likely to casually stroll up to a cat and get eaten… and then all the T. gondii in its belly can reproduce again.

'Tom and Jerry' would've been very dark if toxo was involved.
'Tom and Jerry' would've been very dark if toxo was involved. 

Toxo, clearly, isn’t deadly for cats. It actually works out pretty well for them, since it makes their food much more likely to just walk up to them for the slaughter. It is, however, fatal for a range of species, including sea otters, spinner dolphins, kangaroos, and Hawaiian monk seals, which ingest toxo when cat poo gets washed out to sea. Humans can fall victim to toxo too, although it’s usually only fatal if they have a compromised immune system to start with.

Three endangered monk seals — and one fetus — died last year because of toxo. Two native Hawaiian birds are also falling victim to the creepy-ass parasite. It’s a more significant loss than it sounds, due to small, dwindling populations. Plus, it could be prevented if feral cat populations could be stamped out, since they’re a wildly invasive, destructive species.

Compared to some of the problems environmentalists are facing, taking care of feral cat populations, albeit massive ones, is a surmountable task. However, as Outside documents, cat lovers often stand in the way of such elimination efforts, and the preferred trap, neuter, release (or TNR) method of population control is flawed.

In the meantime, cats will be hunting and pooping zombie spores in Hawaii, the site of 78 percent of all extinctions in the United States … so far.

Photos via Warner Bros. Entertainment., Getty Images

James Grebey is a writer, reporter, and fairly decent cartoonist living in Brooklyn. He's written for SPIN Magazine, BuzzFeed, MAD Magazine, and more. He thinks Double Stuf Oreos are bad and he's ready to die on this hill. James is the weeknights editor at Inverse because content doesn't sleep.