152. Star

Stars (a.k.a. Super Stars, Starmen, Invincibility Stars, or Rainbow Stars) are items used in many Mario games, including the Super Mario series and the Mario Kart series. If Mario gets a Star, he will become Invincible Mario. The user becomes temporarily invulnerable to all damage, except to hazards that would normally be fatal, regardless of powerups (lava, pits, time-over, getting crushed, etc). Any projectiles or enemies that come into contact with the user of the Star while it is activated are either destroyed, damaged, or spun out (depending on the type of enemy and what game it is). The Star also increases the speed of the user substantially.
From Super Mario World and beyond in the Super Mario Bros. series (including several remakes), if the player collides and defeats eight enemies while invincible (five in Super Mario Land 2), they will get a 1-Up. As they continue rampaging through enemies, they will keep getting 1-Ups for each additional enemy steamrolled until the Star wears off completely (as in the player becomes vulnerable again). Touching another Star while already invincible will prolong the effect and allow the player to continue getting 1-Ups.
In most games where stars appear as items, once collected, a theme will play. This theme is just as famous as the Super Mario Bros. theme, leading to remixes and remakes into ringtones.