! Block

Exclamation Mark Blocks (also often shortened in text form to ! Blocks) are floating blocks found in Super Mario World. At first all the player can see is Dotted Line Blocks, which is their outline, but after Mario or Luigi hits one of the ! Switches at the Switch Palaces, they become filled in. Additionally, some Exclamation Mark Blocks contain various power-ups. Yellow blocks contain Super Mushrooms, green blocks contain Cape Feathers, and red and blue blocks contain nothing, but may, like the others, provide extra paths to a short-cut or a secret room.

In Super Mario 64, Exclamation Mark Blocks come in four different colors. Yellow ones contain coins, Stars, 1-Up Mushrooms, or Koopa shells. Red ones contain the Wing Cap, the blue ones contain the Vanish Cap, and the green ones contain the Metal Cap. All ! Blocks (except the yellow variety) must be activated by hitting the corresponding ! Switch. If the switch isn't hit yet, the red, blue and green Exclamation Mark Blocks will be transparent and can not be hit. In Super Mario 64 DS, all Exclamation Mark Blocks were replaced by red ? Blocks. Special powers were based on the character that struck the block and not block colors. If Mario hits one, he'll get either the Wing Cap or will become inflated, if Luigi hits one he'll become invisible, if Wario hits it, he'll become metal, and if Yoshi hits one, he'll get fiery breath.

A few Exclamation Mark Blocks also appear in Mario & Luigi: Superstar Saga and Mario & Luigi: Partners in Time. They have various functions and can activate events. Purple colored ! Blocks are introduced in these games, which have varying effects. Three special Exclamation Mark Blocks in Mario & Luigi: Partners in Time are used to destroy giant Exclamation Mark  Blocks of the same color in Thwomp Volcano, allowing the Mario quartet to traverse further down the volcano. The blue variety later appears in the Star Shrine, where it would change color depending on whether Baby Mario or Baby Luigi hit it.

Exclamation Mark Blocks can also been seen as part of the treasure hoard inside the safe in the Mario Party mini-game Key-pa-Way. Strangely, one of the ! Blocks is purple.

Trivia

 * The item Surprise Ball from Yoshi's Story looks like a round ! Block.
 * In New Super Mario Bros. Wii, there is a red switch which activates red blocks that acts similar to the ones in Super Mario World, but there is no "!" on them.
 * The Super Guide Block of New Super Mario Bros. Wii is a green Exclamation Mark Block.