Replacement for paintballs.

[Ipquarx]

If you put marbles in your paintballs then go shoot yourself in the face with one you starfish.

[Ad Bot]

[Caribou]

Real balls are what's needed 

[th3coolst3r]

lsd

[F3d323]

viruses

[Starkiller]

zombie blood

[Biostorm]

Try injecting them with Ebola or HIV

[Bomberguy]

make brick balls
or balls ( ͡° ͜ʖ ͡°)

[sir dooble]

So basically an air-powered musketball? Sounds smart.

[AcornCake]

liquid nitrogen

[Gytyyhgfffff]

Inject paintballs with liquid mercury.

[Rigel]

Try injecting them with Ebola or HIV

Actually not a bad idea if you're going paintballing with someone you hate.

[F3d323]

Actually not a bad idea if you're going paintballing with someone you hate.

its all fun and revenge until he sneezes on you

[Flatflyer]

Magnesium

[Brickman]

needles of heroin

[Doughboy]

i hear firing a nuclear warhead at your friends is a good idea