When the unicorns went into the sea, untold millennia ago* they shed their hooves and took on blubber to become narwhals, and for the most part, they were happy.
But ages passed and ice melted and the seas were no longer as hospitable as they had been. The narwhals heaved themselves up on the beaches and began the long, slow process of reclaiming the land. If you travel to the most remote islands in the long-lost sea, you can find the land-narwhals frolicking in the surf, gallumphing over the dunes, using their horns to heal (and occasionally skewer) passing seabirds. They are still more agile in water than on land, but given enough time, they may reverse the steps that led them to the sea.
And then we’ll have hippocorns, and I just hope everyone will be happy.
*Red bulls may have been involved. The fossil record is silent on this point.
(Someone told me I was a unicorn today, and I replied that I preferred to be called a land-narwhal, and…well…you know how it is.)