You would probably have heard of Spork, the cross-breed between a spoon and a fork. (No, it's not superman and pork.) Now, meet Knork. The cross-breed between a knife and a fork.
The knife or sharp blade is actually the edge of the fork itself. Now, I can't really testify how sharp it is, but from what I've read, it doesn't cut your skin or your gum. It could be that it's not that sharp, or it could simply be a trade secret. Who knows eh? You try and let me know :)
You can get it at Amazon at USD $22.99 for 4.