Ice Meteor

Frosteors are falling ice crystals that appear in Super Mario Galaxy 2. Frosteors 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 Ice Magma Skate Planet. The ice platforms created by Frosteors will dissipate after a few seconds.

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

Trivia

 * Despite being an independently coded object, Frosteors are not acknowledged in either the Prima Games guide for Super Mario Galaxy 2 or the Super Mario Bros. Encyclopedia.