I remember finding these mimic ideas a while ago. From DS1-3 they never expanded on the enemy/idea, they've always been chests. Hopefully we see some new mimics in Elden Ring. : r/Eldenring
Spider Nest Castle - Nioh Walkthrough - Neoseeker
How to deal with Nurikabe and Mimic in NiOh 2? | gamepressure.com