This knife is real. Virtually every fact you hear about it in this video, however, miiiiiight be slightly exaggerated.

You know what I love about living in the future? We now have the technology to take an idea that almost certainly started with saying "wouldn't it be funny if..." and make it into a reality. Don't get me wrong. Those benighted 20th Century types had some great gag products, but not on the level of "a switchblade sword that will always be hilarious until someone accidentally points the wrong end forward and commits ironic seppuku." Ladies and gentlemen, the Microtech Halo 3x.

Sources: Knife HQ