Cosmic Clone
Cosmic Clones (or Shadow Clones) are shadowy duplicates of Mario or Luigi that appear in Super Mario Galaxy 2. Cosmic Clones are created once a certain point is reached in a galaxy and will follow behind Mario or Luigi, performing every movement Mario makes. Once a certain task is met, such as collecting all five Star Chips, or find an object they will disappear. If Mario touches a clone, he will take damage. Boards usually warn the plumber that Cosmic Clones are present in the area. Cosmic Clones also are able to walk where there is no platform if it is necessary for following Mario. Also, Cosmic Clones will do whatever Mario did, even if the landscape has recently been changed.
The Cosmic Clones most likely replaced Cosmic Mario as Mario's cosmic entity.