In Super Mario World, a ! block is a solid block with a ! on it. Initially, they are boxes made of colored dotted line blocks. Pressing the switch corresponding to their color makes every box of that color into permanently solid ! blocks.
If you insert these blocks through Map16, then the blocks wont need to have a switch palace pressed. It will appeared as colored in ! blocks. Additionally, if you place a non-filled block through Map16, it will never be filled in.
! blocks come in four different colors. They are:
- Yellow: Hitting this from below will give you a Mushroom, regardless of Mario's current form.
- Green: Hitting this from below will give you a Feather, regardless of Mario's current form.
- Red: Hitting this from below will give you nothing.
- Blue: Hitting this from below will give you nothing.
Red and Blue ! Blocks can be made to have powerups via a patch on SMW Central (called "All Switch Blocks Have Powerups"). That same patch can make all four ! Blocks contain nothing.
Dotted Line Blocks
Dotted Line Blocks are how ! blocks will appear when a Switch Palace of that color has not been completed. The color of the dotted lines represent what switch will need to be pressed to make them solid. These are commonly used to access secrets, requiring the player to have completed a Switch Palace in order to find said secret. Note that these tiles if inserted through Direct Map16 Access will always be intangible, even when the switch has been cleared.