It has been proven that 2 animals can be put together to create another. The glowing monkey (jellyfish+monkey) is just a single example of this. (google it). So what if, we were to put a narwhal, and horse together. Could we in fact create a unicorn?
what you get would depend on what genes where used. But you wouldn't end up with a unicorn like creature with such a combination. The narwhal's "unicorn horn" is really a tusk jutting out from it's mouth. So if you where to take this feature in put it on a horse you would end up with a horse with a serious tooth problem.
I CAN MAKE A UNICORN!!! (does some drugs and puts a party hat over a white horses head) YAY A UNICORN. Not unless we genetically engineer one could they ever be real.