Super Mario Galaxy 3, Cosmic Time Travel is a rated M Mario Galaxy Game that involves time travel and explains why there was both a star festival in Super Mario Galaxy and Super Mario Galaxy 2.
Bowser is angry that his plan in Super Mario Galaxy failed so he decided to come up with a second plan to travel back in time grow big by swallowing the grand stars. So he steals professor E Gad's time machine. This caused Proffesor E Gad to get angry, blow up and die, in this reality.
When Bowser travelled back in time and grew big he decided to not only attack Rosalina's starship and steal it's stars but also attack Lubba's as well since he was extra big and powerful. Bowser did this during the daytime before the night of the Star Festival, and attacking Lubba's starship caused shooting stars to fall down early which made the star festival be celebrated in the daytime as shown in Super Mario Galaxy 2.
That was when Bowser attacked the Mushroom Kingdom. Then the events of Super Mario Galaxy 2 happened except that Rosalina didn't show up in the end because her starship was attacked by Bowser and lost it's power stars.
So after defeating Bowser in SMG 2 Mario decided to drive starship Mario to Rosalina's starship to help Baby Luma find Rosalina and to also help find the power stars for Rosalina's starship. However while he is driving it, he keeps mumbling to himself on how he wants to have sex with Princess Peach, which gives him an errection which distracts him from driving the airship.
Therefore once he gets to Rosalina's starship, he forget's to put on the brakes and he crashes into Rosalina's starship causing Starship Mario and Rosalina's starship to blow up into pieces and Luba, his crew, Rosalina, and the Lumas on her ship to die. Mario, Peach and Baby Lumaa go flying off into space and Mario and Baby Luma land on a distant planet where it is raining dead Lumas from the crash as well as the decapitated head of Rosalina.
When Baby Luma sees his mother's decapitated head, he tells Mario, "You fucking asshole! Your sexual thoughts about your Special Bitch's cunt caused the death of my Mama!" Mario gets angry at Baby Luma for saying that so he eats Baby Luma giving him automatic spin power.
He decides to collect the power stars of the destroyed Starship Mario so that he could resurect Starship Mario and go back in time in the Starship to help find Rosalina's power stars during the time his past self was doing adventures in SMG 2. He then gets a letter from Bowser on how he found and kidnapped Peach and that he will try to prevent Mario from finding the Power stars. Mario finds domes on the planet where he can select a galaxy to go to in order to find a power star.
|Grassy Field Galaxy||A galaxy with Grassy Fields||The Goomba King|
|Yoshi Egg Galaxy||A galaxy with Yoshi's||Dark Yoshi|
|Prickly Cactus Galaxy||A galaxy with Prickly Cactuses||Cacti the Giant Mutant Cactus Monster|
|Vine Climb Galaxy||A Galaxy with tall Vines||Craku the Vine Cutter|
|Dirty Diaper Galaxy||A galaxy where the dirty diapers of infant Lumas go to||The Baby Son of Stinky the Shit Monster|
|Big Branch Galaxy||A forest galaxy with tall trees that have leaves that block out the sun making it haunted||Kamella and Kamek|
|Big Waterfall Galaxy||A galaxy with a big waterfall||Dandrik the Dam Breaker|
|Bowser Jr's Shit Reactor||A level where Bowser Jr has a machine that launches his shit at Mario at bullet speed which temporarily traps Mario who gets stuck in the shit so that a bullet bill can go after him||Bowser Jr.|