The Tusk is a primary weapon for the Narwhale.
The Tusk, being the Main Weapon, is firmly mounted on the tip of the Narwhales head, between its 2 beady eyes. It can be used to cut through other Narwhales, if the Narwhale is going at a certain speed.
The Tusk has one ability called Boost, which is used to boost the Narwhale forward in the direction the Tusk is facing. If the tusk touches a Narwhale during a Sprint, the enemy Narwhale will be cut in 2. It is best to only try to cut during a Boost. A Tusk can have up to a max of 4 boosts.
Hitting another Narwhale with your tusk will cause both Narwhales to bounce back, they can bounce back even farther if boost is used.
Your tusk can also have fruit on it if you level up your tusk enough.