Blue switch (Super Mario Galaxy)

A blue switch is a ! Switch functioning as a Ground-Pound Switch that appears in Super Mario Galaxy 2. During gameplay, Mario or Luigi must ground-pound the blue switches. Upon one being pressed, a temporary effect marked with a speeding-up ticking sound occurs, ending with a ding. One freezes the water on a small planetoid in the Cosmic Cove Galaxy, one moves an elevator for a Gold Chomp in the Chompworks Galaxy, and one briefly changes a field of gravity in the Upside Dizzy Galaxy.

In certain stages with unusually fast obstacles, the switches cause the entire screen to turn black and white with a rippling effect, and the music to sound compressed. The main effect of hitting one of these switches, however, is that it will slow down all the obstacles around Mario or Luigi. The switches can allow him to pass under a Thwomp or jump on a fast-moving platform with ease.

Trivia

 * In a pre-release version of Super Mario Galaxy 2, an earlier version of the 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 rails, Water Shooters' bubbles, coins, and Mario or Luigi do not turn black and white when a time-slowing blue switch is pressed.