|“||WHAAAAAAAAAAAAAAAAT?!? You destroyed my precious younger sister?!? I wondered why she hadn't written recently… Quake in fear, mortals! For I am Gloomtail! I will avenge my sister by taking your lives...and then gnawing on your bones!||„|
He was once The Shadow Queen's pet, and is kept in the Palace of Shadow. When Mario entered, Gloomtail was enraged to discover that Mario killed his sister Hooktail, so he attacked him. In the end, he was defeated, and before he "expired" he coughed up a treasure chest containing a star-shaped stone.
Gloomtail is one of the tougher bosses, with 80 HP, 8 ATK and 2 DEF. He can power up and use Megabreath (which is yellow). His regular breath is green and can poison Mario. He can also stomp and create an earthquake.
- He has the fourth strongest enemy attack in the game.
- Gloomtail is somewhat similar to Elder Princess Shroob, as both wanted to avenge their sisters' deaths.
- If Mario brings any of his partners that were unavailable during the battle with Hooktail, they will confuse him for Hooktail, going off on several descriptions Mario told them about offscreen.