Power Star

Power Stars, also referred to as Stars, are collectible items introduced in Super Mario 64 that can grant Mario access to more levels in-game, unlike the similar-looking Super Stars, which only give brief invincibility. In Super Mario 64, Super Mario Galaxy, and Super Mario Galaxy 2, when the star for any given level has been collected, playing the level again will turn the Star into a translucent version of itself (similar to how Star Coins work). This Star can be collected, but it will not add to the player's total Star count.

Super Mario 64
In Super Mario 64, Power Stars are scattered throughout the various courses, most of which pertain to a mission. By obtaining a Power Star, the corresponding mission is cleared. Power Stars either appear in plain sight or after completing a mission objective, such as defeating a boss. There are seven Power Stars in each course; one is a secret Power Star that Mario can obtain from collecting 100 Coins, although these Power Stars are not associated with a mission. The various ★ doors and Big Star Doors of Peach's Castle require Mario to have at least a certain number of Power Stars (which is displayed on normal doors).

There are eight Red Coins in each course, and collecting all of them causes a Power Star to appear over a Star Marker. If Mario has already collected a Power Star, it appears transparent gray on the course. The Jumbo Star does not count toward the Power Star total.

There are a total of 120 Power Stars. 15 of them are Secret Stars, found either in secret areas or are held by a Toad. At least 70 Power Stars are required to access Bowser in the Sky. Once Mario collects all 120 Power Stars, the cannon outside Peach's Castle is then available, giving access to the castle's roof.

Super Mario 64 DS
In Super Mario 64 DS, there are a total of 150 Power Stars, 30 more than in the original game. An extra mission was added in each course, making a total of eight Power Stars per course (one of which is the 100 Coin Star). The game doubles the number of Secret Stars to 30. At least 80 Power Stars are required to enter Bowser in the Sky. Some Power Stars can only be earned by a certain character: 2 for Yoshi, 18 for Mario, 15 for Luigi, and 13 for Wario.

Some courses have a mission where five Silver Stars must be collected for the Power Star to appear in a Star Sphere. If the character loses a Silver Star, the Power Star disappears until they retrieve the Silver Star.

In VS Mode, the objective is for each Yoshi to get the most Power Stars within the time limit. In the mode, most Power Stars are contained within a Star Sphere except for those in The Princess's Secret Slide. If a Yoshi is hit, it drops a Power Star, which bounces around the stage non-stop, much like Silver Stars, until a Yoshi picks it up.

Super Mario Galaxy
Power Stars make a return in the Wii game Super Mario Galaxy, where there are a total of 121 stars to collect each for both Mario and Luigi (for a total of 242). They have a more metallic and rounded appearance than before.

There are four types of Power Stars: First, there are regular Power Stars which serve the same purpose in other 3D Mario games. The second kind is the three Green Stars that, in addition to acting as normal Power Stars, unlock the Green Launch Star in the Comet Observatory which leads to the Trial Galaxies. The third type is the Red Power Star. There is only one in the game; it appears in the Super Mario Galaxy mission "Gateway's Purple Coins". Last are the seven Grand Stars, the first of which, and the only one obtained without a boss fight, is the first star in Gateway Galaxy. Subsequently, the other six Grand Stars are each collected by beating Bowser or Bowser Jr. These power up the Comet Observatory and unlock new Domes to explore. Silver Stars also return from Super Mario 64 DS, working in the same way, though they float alongside Mario once collected, and can't be lost by taking damage.

In Hurry-Scurry Galaxy, as well as the planet that appears in Sea Slide Galaxy when the Hungry Luma transforms in the third mission, collecting notes turns the black hole into a Power Star.

In the game's file system, there is an unused blue texture in the Power Star's data folder, suggesting that Blue Power Stars were originally going to be collectibles, but they were scrapped during development. This was removed in the sequel's file system.

Super Mario Galaxy 2
In Super Mario Galaxy 2, Power Stars play the same role as in Super Mario Galaxy. There are 242 Power Stars in total (116 normal Power Stars, 6 Grand Stars, and 120 Green Stars). If the Cosmic Spirit is used to complete a mission, the star collected will be a Bronze Star instead of a gold one.

Super Mario Maker
Power Stars make a cameo appearance in Super Mario Maker, where both the Captain Toad and Toadette Mystery Mushroom costumes hold up a Power Star in their poses when the player presses.

Super Mario Odyssey
In Super Mario Odyssey's Mushroom Kingdom, Power Moons resemble the original appearance of the Power Stars, even playing the jingle that plays upon collecting a Power Star in Super Mario 64 when they are collected, which replaces the standard Power Moon jingle in this kingdom. Cappy, when Mario collects his first Mushroom Kingdom Power Moon, suggests that Power Moons come in different shapes. When loaded into the Odyssey in the Mushroom Kingdom, they appear as regular Power Moons.

Mario Pinball Land
Stars reappear in Mario Pinball Land, working just like they do in Super Mario 64, obtained after completing certain trials, such as defeating a boss or a certain number of enemies in time, and their use is to make Mario's way to Bowser. At the end, the number of Stars obtained determines how much the point bonus is worth.

Super Smash Bros. for Nintendo 3DS / Wii U
A Power Star appears in Rosalina's Final Smash in Super Smash Bros. for Nintendo 3DS and Super Smash Bros. for Wii U. In Super Smash Bros. Ultimate, it is replaced with a Grand Star.

Captain Toad: Treasure Tracker
Power Stars reappear in Captain Toad: Treasure Tracker, appearing at the end of each stage. However, unlike in previous 3D platformers, which has the Power Stars counted when collected, the game does not count Power Stars, treating them more as Goal Poles in that they only serve to be the end of the level.

Variants
There are several variations of the Power Star, some of which serve a different purpose from that of normal ones.

Trivia

 * While Power Stars themselves do not appear in Super Mario 3D World and Super Mario Sunshine, the Green Stars and Shine Sprites work similarly, unlocking levels should enough be collected.
 * In the Super Mario Mash-up in Minecraft, a Power Star makes a small appearance on a painting of a Big Star Door.
 * The jingle that plays when collecting a Power Star in Super Mario 64 (a rearrangement of Bob-omb Battlefield's theme) was arranged in Super Mario Odyssey as the jingle that plays when collecting a Power Moon. The original jingle plays in the Mushroom Kingdom.
 * The music that plays in the Moon Kingdom in Super Mario Odyssey shares similarities with the ambient music heard in Super Mario Galaxy and its sequel before Mario/Luigi collects a Power/Grand Star in certain missions.