This being a physics forum, I'm sure many of you have heard of the 1998 computer game Half-Life. If you don't know, the game is set within a top secret research laboratory deep within the deserts and mesas of Arizona. All hell breaks loose after a massive screwed-up experiment. The protagonist is a theoretical physicist who has to somehow survive. Anyway, at the start of the game you travel across a canal filled with some glowing green sludge. http://www.youtube.com/watch?gl=US&hl=en&client=mv-google&v=qUDNiyOf92o&nomobile=1 (its near the end of this video) I'm extremely curious as to what the sludge could be. Apparently its radioactive. But does radioactive fluid glow like that? Is there such a thing in real life? In the game there is also a weapon called the Gluon Gun. Its pure fiction, but I wonder, is it possible to create a stream of gluons like a stream of photons? A gluon "laser" perhaps? After all, gluons can all occupy the same quantum state.