Blue switch (Super Mario Galaxy)

A Blue Switch is an item that appears in Super Mario Galaxy 2, usually during levels with unusually fast-moving obstacles. During gameplay, Mario or Luigi must Ground Pound them. Once Ground Pounded, the entire screen will turn black and white with a rippling effect, and the music will sound distorted, as if it were coming out of a radio. The main effect of hitting the switch, however, is that it will slow down all the obstacles around Mario or Luigi. They can allow them to pass under a Thwomp or jump on a fast-moving platform with ease. The switches only last for a few seconds though, so the player must move quickly to make it through the level in time. Blue Switches appear in only three galaxies: the Space Storm Galaxy, the Clockwork Ruins Galaxy, and the Stone Cyclone Galaxy.

Trivia

 * In a pre-release version of Super Mario Galaxy 2, an earlier version of a Blue Switch was shown as a sort of "side-flipping" switch, as opposed to looking more like a ! Switch.
 * Sentry Beams' lasers, Amps' electricity, Electric Fences, Water Shooters' bubbles and Coins don't turn black and white when a Blue Switch is pressed.