Fear, the ever-powerful unpleasant feeling of real or imagined risk or danger, can be controlled by a certain substance: cat's pee. Well, not exactly cat's pee, but the parasite that thrives in it.

This parasite, known as Toxoplasma gondii, is a parasitic germ whose primary hosts are cats. The parasite may also thrive in most warm-blooded animals, and even humans. It's been estimated that half of the world population is infected by this parasite, altering human fears and even determining human culture.

Neuroscientists from the Stanford University found out that this very same parasite can target certain fears very accurately. For example, rats have an instinctive fear of cat's pee. When infected with the T. gondii parasite, however, rats begin to develop a liking for cat's pee so much that the rodents start hanging out on areas that smell of kitty's wee-wee, making them easy kitty lunch.

The explanation is that the parasites like cat hosts better, because only in cats can they reproduce sexually. The parasites reproduce asexually in other species. Living in cats' brains will make the parasites start their sexual stage in life.

The scientists believe that if they unlock the secrets of the T. gondii parasite, they may be able to use it to favor humanity, being able to modify human fears and phobias. The parasites are known to thrive in the amygdala, a region of the human brain related to fears.

Now the question is, what if we start liking what we fear? That would be like, creepy ... in a likeable way.