How to Befriend it
When the player reaches a certain point in the quest "Be the Best Trainer!", one of the objectives will be to befriend this creature. She will only show up when the quest is activated.
When the player goes to befriend her, they will have to dive with Oceana during a snowstorm in the North Coast of Canada area. After swimming to a certain hole in the ice and going to the surface, the player will have to watch the Narwhals surface in order to spot her trademark red tusk, because she has a tendency to disappear. Because of this, the most effective way to find her is to spot her while she's surfacing for air and then reenter the water immediately after.
After the player has befriended her, this Narwhal can help them befriend another dolphin partner, this time all the way across the world in the Cortica River. The strange, all-pink Amazon River Dolphin will only respond to the player if they have the Red-Tusked Narwhal with them, because it seems to respond better to female animals than humans of any gender.
There is a legend behind this particular Narwhal's distinctive appearance. The stories state that she was once a fierce warrior who used a spear in battle, but upon entering the water on one fateful day, she transformed into a Narwhal with a red-stained tusk.