Magic Stone Dealer Lapis Lazuli

from ebookjapan:

"Hm? Was this shop always here?" Appearing wherever there's a little space in ordinary locations is the mysterious jewelry shop, Talisman. If you have the misfortune to set foot inside, the mysterious jeweler Lapis Lazuli will greet you: "Did you know? This 'Lapis Lazuli,' a jewel with the same name as me, has the power to make any dream come true. Would you like me to sell one, just one, to you? The price is the gem from your soul, your 'heartstone.' Too bad your dream-come-true will be a nightmare..."
It scares the readers of Bessatsu Corocoro* every issue, but it's a unique horror story that many can't help but read.

*A magazine published by Shougakukan featuring manga aimed at young children.