- "Get yerselves ready to...BAAAAAATTLE!"
- ― Grubba
Grubba is a blue Clubba that wears a black and green vest with a black hat. He also wears shades, has orange hair, and his shell is purple.
HistoryGrubba is first seen hosting a match between Rawk Hawk and The Koopinator. Rawk Hawk wins the match and Grubba awards Rawk Hawk with the Champ's Belt. Sooner or later, Mario enters his room and is happy to see another new challenger. He dubs Mario "The Great Gonzales" and sends him to the minor league room. After some time later, Grubba realizes that Mario is searching for the Crystal Star and sends a threatening mail to him. Grubba even suspects his assistant Jolene may be plotting against him as well. After Mario finds his blueprints in his drawer, he makes for the ring where he reveals that he sucked up all of the energy from the other fighters to keep himself younger and stronger. Using the Crystal Star, he then transforms into Macho Grubba and fights Mario. Mario defeats him and, after turning back to normal, Grubba reveals that he was also responsible for the disappearance of the last champ of the Glitz Pit: Prince Mush. However, Prince Mush suddenly emerges from the machine and Grubba is left there on the ground. It is unknown what became of Grubba after those events.
- There is a similarity between Tubba Blubba and Grubba. Both of them look similar to each other, both have blue skin color, and both are Chapter 3 bosses. Also, the names Blubba and Grubba sound similar to each other and they both belong to the Clubba family. Both have Spikes on their Shell, although regular Clubbas don't have spikes, lastly, they both have a well-guarded secret to their "invincibility". Tubba Blubba got his by siding with Bowser while Grubba got his through the Power-draining machine. However while Tubba Blubba was motivated by the fact that he was bullied by the Boos, Grubba was motivated so he could stay young.
- The Stone Spikes in New Super Mario Bros. Wii also resemble Grubba.
- Aside from Cortez, Grubba is the only chapter villain to work independently of the X-Nauts or Shadow Queen, as well as not even being known to associate with them however unlike Cortez, he doesn't reform after his defeat.
- Grubba is the only chapter villain who used his Crystal Star the way it's supposed to be used, which would be the Power Lift special. All other chapter villains either possess a Crystal Star, but never use it, or simply obstruct the path to it.
- Grubba's power-draining methods could be a reference to real life celebrities who have abused their positions.