Power Moon

Power Moons are collectible items in Super Mario Odyssey. Equivalent to the Power Stars in Super Mario 64 (and its remake), Super Mario Galaxy, and Super Mario Galaxy 2, and Shine Sprites in Super Mario Sunshine, they can be found in the various kingdoms of the game and used to power the Odyssey in order to let Mario reach additional kingdoms. Collecting 250 Power Moons unlocks the Dark Side, while collecting 500 Power Moons unlocks the Darker Side. Collecting 880 Power Moons, not counting the additional ones that can be bought at Crazy Cap after completing the main story will turn the Odyssey's sail into a golden color, and unlocks a painting in the Wedding Hall at Honeylune Ridge that allows players to play through a harder version of the final battle with Bowser. Collecting 5 Moon Shards yields a Power Moon as well.

Gameplay-wise, they act mostly like the Power Stars and Shine Sprites in earlier titles, being the main collectible Mario needs to find to progress. Unlike these however, there are between 1 and 104 per kingdom, and completing them does not cause Mario to exit the stage unlike in prior 3D Mario titles (except for Super Mario 3D Land and Super Mario 3D World which instead follow the formula of the 2D Super Mario games and feature Goal Poles instead). Power Moons are also replaced with clear replicas after they have been collected, much like the Power Stars and Shine Sprites, and count as five global coins each when collected again. Power Moons also restore the player's Health Meter and air meter (if swimming) when collected.

Larger variants called Multi Moons also exist in the game. These count as three Power Moons in one, and can be attained by defeating bosses or clearing main story missions.

Including the three-moon count from Multi Moons and post-game store moons, there is a numerical total of 999 Power Moons available in the game. Any moons brought afterwards won't add to the number.

Colors
Power Moons feature a different color depending on the kingdom in which they are found. Their color also matches the color of the pole of the Kingdom's Checkpoint Flag.

Trivia

 * When Mario collects his first Power Star in the Mushroom Kingdom, Cappy says that he didn't know that Power Moons come in different shapes. This may suggest that Power Moons and Power Stars are different shapes of the same object, a distinction that may also include the more rounded-off, metallic-looking Power Stars of Super Mario Galaxy and Super Mario Galaxy 2.
 * When Mario collects a Power Moon, he'll perform three variations of the same pose that change his right hand's gesture, all three of which are callbacks to three previous Mario titles:
 * A victory sign pose, referencing Super Mario 64
 * An open palm, referencing Super Mario Sunshine
 * A closed fist, referencing Super Mario Galaxy