Soccer Ball

A Soccer Ball, also called a Football, is the main focus of the games Super Mario Strikers and Mario Strikers Charged. In these games, players have to gain control of the Soccer Ball and kick it into the goal, something done with either normal kicks, charge shots, Super Strikes (Super Mario Strikers), Mega Strikes (Mario Strikers Charged), or Skillshots. A normal kick, a charged shot, and a Skillshot result in one point; a Super Strike will score a player two, while a Mega Strike can offer up to six for a team.

In Mario Strikers Charged, the soccer ball is made out of metal, which emits a light that indicates the power of the ball. The ball tends to emit a purple light when unused. In this case, shooting the ball results making a failed score. However, charging the ball by passing or charging the shot, players can turn the light into red, yellow and white, the last indicating the ball is charged enough to make an accurate goal.

Apparently, if pressed hard enough, the ball may explode. This is seen in one of Wario's losing cut-scenes, in which he angrily squeezes the ball until it suddenly explodes.

Super Mario 3D World
While common soccer balls don't appear in Super Mario 3D World, bombs designed after them are introduced.

Super Smash Bros. Brawl
In Super Smash Bros. Brawl, the Soccer Ball appears as an item, appearing with its design from Super Mario Strikers. This item cannot be grabbed, however. To use it, it must be attacked, which sends it flying across the stage, catching on fire. The soccer ball does not follow an arc when it is attacked. Rather, it shoots in a straight line before suddenly losing all momentum and dropping to the ground, or off the stage. If it hits opponents mid-air, they are flung away. It is also a trophy that can be randomly unlocked.

Super Smash Bros. for Nintendo 3DS / Wii U
In the upcoming Super Smash Bros. for Nintendo 3DS / Wii U, the Soccer Ball from the game Wii Fit will appear along with the character from said game, Wii Fit Trainer.

Trivia

 * Soccer Balls were planned to appear in Super Mario Sunshine (where they would work identically to the final Durians), as shown in the final game's test level (accessible by hacking) and an early demonstration.