Dream Stone

The Dream Stone is an ancient Pi'illo artifact appearing in Mario & Luigi: Dream Team. The Dream Stone is a rainbow-colored stone in the shape of a spiral. It is said to grant the wishes of anyone who possesses it. It is made up of happy dreams and like the Dark Stone, it can grant wishes.

History
The Dream Stone is first mentioned by Eldream after Bowser and Antasma are defeated in Dream's Deep. He suggests that Mario and Luigi head to Dozing Sands where the Dream Stone is located before Bowser and Antasma can get to it. After defeating Torkscrew, it is revealed that Bowser and Antasma had reached the area before Mario and Luigi and have taken the Dream Stone. Mario and Dreamy Luigi eventually confront the Dream Stone Soul in Dreamy Dozing Sands, who tells them that the actual Dream Stone was taken to Mount Pajamaja.

Bowser and Antasma, along with Kamek and the Elite Trio, are found on the peak of Mount Pajamaja with the Dream Stone. When Mario and Luigi reach them, Private Goomp turns on some speakers which begin playing the Dreambeats. Mario and Luigi escape before they could fall asleep, but the Dreambeats manage to spread across the entire island, putting everyone to sleep. The Dream Stone collects the energy from the sleeping inhabitants, powering it up. Once the Dream Stone is powered up, Antasma and Bowser wish for a castle, which Bowser promptly dubs Neo Bowser Castle.

Near the end of the game in Neo Bowser Castle, Antasma reveals that his wish from the Dream Stone was to create dream portals anywhere he pleases. After he is defeated, Mario and Luigi attempt to rescue Princess Peach, but are stopped by Bowser. Before Bowser can finish of the two, Prince Dreambert demands that Starlow and Peach destroy the Dream Stone. After the Dream Stone is shattered, Bowser inhales the shards of the broken Dream Stone and transforms into Dreamy Bowser.

At the end of the game, Prince Dreambert, with the help of the other inhabitants of Pi'illo Island, collects the dust that Bowser spat out and gives it to Zeekeeper to restore the Dream Stone. He instead, however, uses the dust to create a "Dream Coin", which he then shatters to shower the entire island in coins.

Trivia

 * The Dream Stone is the first major object in the Mario & Luigi series that is not a star. Mario & Luigi: Superstar Saga had the Beanstar, Mario & Luigi: Partners in Time had the Cobalt Star, and Mario & Luigi: Bowser's Inside Story had the Dark Star.