Tyrunt was Grant's second Pokémon he uses in his Gym battle. Froakie started off with Double Team to confuse Tyrunt, but Tyrunt used Rock Tomb in an attempt to destroy the clones. Nonetheless, Froakie leapt on the rocks, and used a Bubble barrage on Tyrunt, but Tyrunt leapt out and unleashed Draco Meteor. This banished all of the Froakie's illusions and hit the real one, defeating it. Ash sent Fletchling, who used Razor Wind to no avail, and tried confusing him with Double Team. But unlike Froakie, Tyrunt made quick work of the clones with Dragon Tail, and took a Steel Wing from the real one before regaining his composure instantly and using Dragon Tail on the real one, knocking it out instantly. Pikachu closed the battle, as it becomes a one on one. Pikachu used Quick Attack, but Tyrunt prepared to counter with Crunch. As the two were about to collide attacks, Pikachu jumped high into the air. Tyrunt used Draco Meteor, but Pikachu hit it with Iron Tail, and knocked the meteors away with the same move. Tyrunt countered with Dragon Tail and the moves collide. Realizing that neither would faint, Tyrunt used Rock Tomb on Pikachu, but he knocked them away with Iron Tail. However, as Tyrunt roared angrily, this was his demise, as a rock was hit in its mouth, blocking off Crunch and Draco Meteor. Pikachu used Quick Attack to move along the rocks, and used a Thunderbolt. In addition to doing massive damage, it slammed Tyrunt back into a wall, doing massive damage and finishing it off.
Grant, Tyrunt and the Gym Leaders came to stop the Giant Rock. Together, they launched a blast that hit the Giant Rock, enough to free Serena's Braixen, Alain's Mega Charizard, Ash-Greninja, Steven's Mega Metagross and Professor Sycamore's Mega Garchomp. Tyrunt helped in the attack against the Giant Rock, by using Rock Tomb against the plants. After Ash and Alain rescued Chespie, the Giant Rock stopped, allowing the group to fire an attack to destroy the Giant Rock. Tyrunt watched as Lysandre appeared while Squishy and Z-2 combined their efforts to destroy the Giant Rock and defeat the villainous Team Flare leader once and for all.
Ash remembered Grant and his Tyrunt fighting the Giant Rock with the rest when he was reflecting back on his journey.