While it’s baffling to imagine any rational adult intentionally deciding to lick a video game cartridge, a few gamers doing just that with Nintendo Switch cartridges were surprised to find the things taste absolutely awful. Turns out, that’s for a very good reason.

The first gaming journalist to take note of the nasty taste warned others against the practice on Twitter last week:

I put that Switch cart in my mouth and I'm not sure what those things are made of but I can still taste it. Do not try this at home. — Jeff Gerstmann (@jeffgerstmann) February 25, 2017

Kotaku’s Mike Fahey writes that as more gamers got their hands on the new video game console — which will be released widely tomorrow — everyone, including himself, agreed that the thing tastes horrible. He also tasted the cartridge, alongside a few other game cartridges to look for a pattern.

Some of the others had hint of bitterness, he says, but tasting the Switch cartridge is “the worst thing you can do to your tongue.”

Nintendo has now confirmed rumors that perhaps the cartridges taste bad on purpose, saying in a statement that it coats them with the same stuff used to keep people from biting their nails so that children won’t be tempted to eat them.

“To avoid the possibility of accidental ingestion, keep the game card away from young children,” the company said. “A bittering agent (Denatonium Benzoate) has also been applied to the game card. This bittering agent is non-toxic.”

In other words, it won’t poison you, but it will make you wish you could chew your own tongue off.