A small, sadistic candy confection is for sale at an old-fashioned Brooklyn sweets shop.

Behind the counter at seven-year-old Park Slope candy store Fferins, right under some Japanese KitKats, sits a box decorated with flames, containing “Lil’ Nitro: The World’s Hottest Gummy Bear!”

The box claims the candy is infused with 9 million-Scoville-unit chili extract, referring to a measure of spiciness. The famously hot Ghost pepper is rated at around 1 million Scoville units.

Lil’ Nitro costs just over $8 and comes with a “consume-at-your-own-risk” warning.

Hayley McGrath, who co-owns Fferins with her wife, said she has been stocking Lil’ Nitros for about three years and typically sells a couple a week, mainly to younger people. But buyers must find somewhere else to consume the candy, she said.

“ I don't want them to have it here. I tell them to do it elsewhere,” McGrath said. “I’ve seen people that have had it — they cried, lay on the floor, state of undress, rocking. There was lots of milk involved.”

The people she referred to are her own teenage kids, who McGrath said split a Lil’ Nitro about a year ago. “They were not OK for maybe, like, 90 minutes,” she recalled.

Whenever customers try to buy a Lil’ Nitro, McGrath said she warns them about how hot and painful the confection is, though she added that she has never personally consumed one. “I know it’s going to hurt me so why would I do that?” she said.

I did not heed this warning, and purchased a Lil’ Nitro — for journalism.

Now I, too, can attest to the power of the thumb-sized red bear. It really is very hot.

I gnawed off a single foot and the flavorless heat was very, very real. Not to brag, but the jug of milk I bought to accompany the experience, per McGrath’s advice, proved unnecessary.

The burning flavor of the bear foot lingered for about five minutes, but it was not overpowering. It was perhaps comparable to a large bite of a particularly spicy jalapeño. I did not shed a single tear.

The bears are the creation of a Missouri-based company called Flamethrower Candy, which puts out an array of superlatively spicy confections.

Lil’ Nitro is not even Flamethrower's hottest offering — that would be the Toe of Satan, which the company warns is for adults only and is so spicy that it “has the potential to cause skin and/or mouth irritation." Flamethrower claims the Toe is among the world's spiciest candies.

Maybe one day I’ll try that, but not today, Satan.