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 be made up of happy dreams and grant the wishes of anyone who possessed it.

History
The Dream Stone is first mentioned by Prince Dreambert when he explained the disappearance of the Pi'illo race: The Pi'illos were entrusted with the protection of the Dream Stone as well as its counterpart, the Dark Stone. But then the evil bat king, Antasma stole the Dark Stone and shattered it before being sealed into the Dream World, causing its Nightmare Chunks to send the Pi'illos into a deep slumber.

After Antasma escapes Dream's Deep alongside Bowser, the Dream Stone is mentioned again by Eldream, stating that Antasma will likely go after it now that he is free. He suggests that Mario and Luigi head to Dozing Sands where the Dream Stone is located before Bowser and Antasma can get to it. However, after defeating Torkscrew, it is revealed that Bowser and Antasma have beaten Mario and Luigi to the Dream Stone. Antasma states that since he could not have the Dark Stone, the Dream Stone would have to do for his plans, and then flees the area with Bowser. Mario and Dreamy Luigi chase down the Dream Stone's spirit in Dreamy Dozing Sands, who eventually tells them that the Dream Stone was taken to Mount Pajamaja.

Bowser and Antasma, along with Kamek and the Elite Trio, are later 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, Bowser betrays Antasma and takes the Dream Stone for himself. Due to this, Antasma swears to have his revenge on Bowser after defeating the heroes, revealing that his ability to create dream portals wherever and whenever he pleased came from his wish to the Dream Stone. After Antasma is defeated, Bowser attempts to wish the Mario Bros. out of existence with the Dream Stone, but was stopped by Starlow and Princess Peach, who also destroy the Dream Stone at the behest of Prince Dreambert. After the Dream Stone is shattered, Bowser desperately inhales the shards of the broken Dream Stone, transforming him 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. However, the Zeekeeper instead 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 artifact in the Mario & Luigi series that is not star-related. 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 and the star-shaped Miracle Cure (which is comprised of the three Star Cures).

Pietra onirica