Blue switch (Super Mario Galaxy)

A blue switch is a ! Switch functioning as a Ground-Pound Switch that appears in Super Mario Galaxy. 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. Two appear in the Beach Bowl Galaxy, where they briefly spawn wooden platforms, and they also appear in the Bubble Breeze Galaxy, where they open alternate paths.

Blue switches return with similar roles in Super Mario Galaxy 2. 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 Upside Dizzy Galaxy. In certain stages with unusually fast obstacles, found in the Space Storm Galaxy, Clockwork Ruins Galaxy, and Stone Cyclone Galaxy, 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 slows 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

 * A similarly acting switch appears in the Gold Leaf Galaxy on the Star Bunny chase planet, but it instead uses the design of the switches from the Dusty Dune Galaxy.
 * In a pre-release version of Super Mario Galaxy 2, an alternate design of the blue switch was shown as a sort of "side-flipping" switch, as opposed to looking more like a ! Switch.
 * Spring Vaults' 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.