This is the Ultimate Sniper Stock, for the ultimate ninja. Ninjas are so accurate with it that they can hit a penny from over 10 miles away. This gun is manufactured by Choate Machine and Tool and built of DuPont Rynite SST-35 polymer.
This is the BFG-10k. You can find out what it stands for on your own. Ninjas do not use this weapon very often, because ninjas like to be stealthy. But sometimes when ninjas just feel like freakn' out on a whole army or something they use it. This gun is not thought to be real, but it is, only ninjas have it. You can see the animated version in Quake 3 Arena.