POW Block

The POW Block, also occasionally referred to simply as "POW", is an item that appears in Mario Bros. (the arcade version and its ports; not the Game & Watch one). When hit, it damages all enemies in the screen, but only those that were on the ground. It performs the same function in Super Mario Bros. 2, but it can only be used once as the player has to throw it onto the ground to make a POW.

In Super Mario World 2: Yoshi's Island, if Yoshi hits a POW block, all nearby enemies turn into stars. POW Blocks were most commonly won in Bonus Challenges, where they could be used anywhere afterwards, being called Anywhere POWs.

In the Paper Mario series, the POW Block is an item that does two damage to all enemies (but much more in Super Paper Mario if the remote had been shaken with each corresponding prompt). It penetrates defense and makes enemies with shells (such as Koopa Troopas) turn over. It does not affect flying enemies, however, unless they are on the ceiling.

The POW Block is a new item in Mario Kart Wii. When dispatched by a player, other racers will find POW Blocks above their karts. They must jump three times (in rhythm) to destory the POW Block or they will spin out and lose speed.

Trivia
In Mario Kart: Double Dash!!, even though there are no POW Blocks in the game, "POW" can be seen in a license plate of cars in Mushroom City and Mushroom Bridge.