Walubba is the primary antagonist of Mario Galaxy: Walubba's Wrath and is known as Lubba's doppelganger, similar to the relationship between Wario and Mario. He was discovered by Mario in Gamma Pajama galaxy after gamma rays duplicated and mutated Lubba.
Walubba is very features a striking resemblence to Lubba (as would be expected), however, Walubba is neon green with orange pants. His eyes are beady and someone bulging with an orange unibrown covering them. Walubba's smile is very sinister and creepy. Finally, Walubba has a dark green tattoo shaped like an upside-down star on his chest.
Walubba is incredibly greedy, with greed rivaling or even surpassing that of Wario. He can also be enraged extremely easily and has a strong desire for revenge. This is evidenced in Mario Galaxy: Walubba's Wrath when he discovers Moneyruption Galaxy, which Wario and Waluigi had promised to be an oasis with volcanoes that spew coins. When he sees that it is in fact a desolate wasteland, he locks Wario and Waluigi up and blows up the entire galaxy.
Walubba can fly relatively fast as well as shoot lasers from the orb on his head. In addition, Walubba has the ability to summon meteors which can easily crush all who oppose or question him.
Mario Galaxy: Walubba's Wrath
Walubba is first introduced in this game. At first, he dwells at the location of his creation, Gamma Pajama Galaxy. When Mario and Lubba disturb him, he shoots lasers at them and they flee instantly. Having observed Walubba's abilities from afar, Wario and Waluigi request he keep Mario at bay while they proceed with their plans. In exchange, they promised to pay Walubba a large portion of the loot they collected from Moneyruption Galaxy.
When Walubba sees that the galaxy is a wasteland, he locks Wario and Waluigi up and plots to blow up the entire galaxy along with Mario, Lubba, Wario, Waluigi, and the Spaceship Mario. However, as he sets off the explosives Mario and Lubba beat him back to the Spaceship Mario and escape just before Walubba, Wario, and Waluigi are caught in a massive explosion. Afterwards, the trio are seen floating in space, conspiring to destroy Mario. But Bowser, along with all the bosses from Mario Galaxy: Walubba's Wrath appear and offer to become allies and form a team which will overpower Mario. They present the bait they need: Princess Peach.