Gem of Aicheizi
The Gem of Aicheizi is an object featured in the Game Boy issue "Pipes is Pipes". Dubbed "the most valued gem in all of Sarasaland" by Tatanga, its history and nature are not elaborated upon.
Upon warping into the real world, Tatanga offers the gem as a birthday gift to an unimpressed Princess Daisy, who tries to escape instead. Much later, when Tatanga grows bored of the birthday celebration, Daisy quickly tosses the gem to Michael Hallis as Tatanga's forces warp back to the Game Boy. Micheal's mother and Mario arrive, and Mario explains he can only go back to the Game Boy world while Tatanga's machines are keeping a Warp Corridor open.
Pionpi pops out of a new portal and ask Michael to give him back the gem, giving Mario an opportunity to sneak into the portal. Michael obliges and Pionpi returns to the Game Boy world in turn.