* Narwhals are marine mammals (cetaceans) closely related to beluga whales. They have a single, long, spiraled tusk (actually a modified tooth) on their upper jaw.
* Horses are land mammals (equines) that are adapted to running and grazing.
There is no way to create a hybrid between these two animals through natural breeding.
This is like asking what a giraffe crossed with a fish would be - it's not possible! 😊