Emerald Star

From the Super Mario Wiki

The Emerald Star is the second Crystal Star and was found in The Great Tree in Paper Mario: The Thousand-Year Door. It was stolen by Lord Crump, but given to Mario by the Puni Elder after driving the X-Nauts out of the tree. This Crystal Star will teach Mario the move Clock Out, which costs 2 SP. To use this move, you must repeatedly press the button that appears on the opponents side of the field. If done correctly, enemies will be immobilized for a few turns. Be careful! The buttons will change at random intervals, and you may end up freezing yourself! The audience may be also frozen if it is neither on Mario and his partners' side or the enemies' side. But beware because the Shy Guys can protect the enemies from this attack.

Crystal Stars
Diamond Star | Emerald Star | Gold Star | Ruby Star | Sapphire Star | Garnet Star | Crystal Star

Stars

Beanstar | Big Star | Bonus Star (Mario Party) | Bonus Star (Super Mario World) | Cobalt Star | Crystal Star | Crystal Stars | Diamond Star | Dark Star | Eldstar | Emerald Star | Garnet Star | Giant Power Star | Gold Star | Grand Star | Green Power Star | Kalmar | Klevar | Launch Star | Luma | Mamar | Millennium Star | Misstar | Muskular | Polari | Power Star | Pull Star | Rainbow Star | Red Power Star | Red Star | Ruby Star | Sapphire Star | Shine Sprite | Shooting Star | Silver Star | Skolar | Sling Star | Star | Star (Donkey Kong) | Star (species) | Star Piece | Star Spirits | Starslap | Star (outer space) | Twink | Warp Star | Zeostar