This piece originally appeared on newstatesman.com.

The worst thing about going through airport security and having, say, your sweet, sweet honey confiscated, is that you can probably buy a replacement from at least one of the shops in the area between the security gates and the departure gates. This security theatre is justified on the grounds that only stuff that’s harmless is allowed beyond a certain point - so it follows to reason that everything those shops sell should be pretty much useless when it comes to taking over a plane.

Except, no.

That is the BLUNDERBUSSiness Class, as designed by security researcher and computer programmer Evan Booth. Everything you see there was bought from stores within an airport, and the weapon exploits some simple chemical reactions.

A battery in the “gun” runs an electric current through a piece of wire when the trigger is pulled, melting the condom with heat. The water from the condom mixes with the lithium, and that reaction heats up the deodorant can so quickly that it explodes, forcing the “shot” - in this case, pennies - out of the rolled-up magazine barrel.

There’s a fair chance it would take your arm off with it, but it also puts those coins through a partition wall, so it counts as a weapon.