When Flintlocke was transported to the arctic by Nadakhan thanks to his second wish, the Treehorn Queen attacked him, chasing the pirate across the falling, icy stalactites. However, he escaped her when he wished to be on a pirate ship, transporting Flintlocke to the Misfortune's Keep.
After Zane saved the rest of the ninja from their ambush, the Treehorns called on their queen to help them. Arriving to support them, the Treehorn Queen angrily confronted Zane, and determined to protect his friends, the latter unlocked his True Potential and froze her solid, presumably killing the Treehorn Queen.
The Treehorn queen looks like a normal treehorn, but much larger with bigger fangs and giant red eyes.