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Super Mario 3D All-Stars

Comet Star: Underwater Cosmic Mario Race

Ben Chard
Jarrod Garripoli
, &
Seren Morgan-Roberts


This page offers a walkthrough for the Underwater Cosmic Mario Race Power Star in Sea Slide Galaxy. This galaxy is found in the Engine dome.

Challenged by Cosmic Mario

Landing on the starting island, Cosmic Mario will appear and challenge you to a race. You start the race by running into the water and begin swimming. This will be harder than racing penguins, as Cosmic Mario will use ride a shell to swim through the water.

Cosmic Mario will materialize a shell and cannot be hit by thrown Red Shells.

Be sure to grab a shell of your own to keep up. You will need to use the rings to boost past Cosmic Mario. Red Shells wont be able to hit Cosmic Mario. You wont need to go round the complete course this time, as you will see arrows pointing Mario to go back on land with the tower. The Power Star will be set behind the tower.

Head out the water, onto land and up the steps. When you’re on land you can throw the shell and make your way to the Power Star that should be next to the tower. Be sure not to hesitate as Cosmic Mario will be close behind.

(1 of 2) There will be one last mad dash on land to reach the Power Star

There will be one last mad dash on land to reach the Power Star (left), you just need to grab it before Cosmic Mario to win the race! (right)

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Guide Information
  • Publisher
  • Platforms,
  • Genre
    Action Adventure, Platformer
  • Guide Release
    24 September 2020
  • Last Updated
    8 February 2021
    Version History
  • Guide Author
    Seren Morgan-Roberts, Jarrod Garripoli, Ben Chard

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This guide for Super Mario 3D All-Stars offers a walkthrough for all three Mario classics.

Inside this guide you will find:

A 100% Walkthrough - For Super Mario 64, Super Mario Sunshine and Super Mario Galaxy.

A complete guide on Super Mario 64, including:

  • A layout of Peach’s Castle, with each course’s location pinpointed, as well as an overview of each course.
  • Walkthroughs for every star, including all courses’ 100-coin star.
  • How to get each of the power-up caps.
  • The location of every single Secret Star found in Peach’s Castle.

A complete guide on Super Mario Galaxy, including:

  • A Dome Overviews page outlining every galaxy found in each Dome.
  • Walkthroughs for every star, including hidden stars and comet stars, found in each galaxy.
  • A guide on how to unlock the Planet of the Trials galaxies.
  • Detailed coin-by-coin walkthroughs of Purple Coin levels.

A complete guide on Super Mario Sunshine, including:

  • Walkthroughs for every shine in every episode.
  • How to find every Blue Coin.
  • Strategies on how to secure 100 Coins on every Course.

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