Ice Meteor

Ice crystals are objects that appear in Super Mario Galaxy 2. They only appear on the Shiverburn Galaxy in the mission Prince Pikante's Peppery Mood, where they fall from the sky into the lava pond on the Ice Magma Skate Planet, creating ice platforms which Mario can skate across to the Launch Star at the end of the planet. This is a logical inversion of the earlier half of the planet, which featured meteors raining down on the icy half of the planet. The ice platforms will dissipate after a few seconds.

Although the ice crystals are necessary to help Mario reach the planet's Launch Star, touching one before it hits the lava will freeze Mario, causing him to take damage. The ice platforms the crystals leave behind are identical to the ones created by Ice Mario from Super Mario Galaxy.

Trivia

 * Despite being an independently coded object, ice crystals are not acknowledged in the Prima Games guide for Super Mario Galaxy 2.