Rain Dinners Aquarium Death-Trap Fish-Tank Sinking-Room

Status: pending (resolves in subsequent chapters) · Technique: chekhov-explicit + villain-architecture-trap

The seed

First on-page Crocodile-tier engineered-architecture villain-trap.
The cage from Ch. 0170 is re-coded from a hold-cell to a kill-room: the floor opens into a Bananagator pen, the windows admit Rainbase Lake water, the room sinks below water level on a timer.
Pre-loads the Sea-Prism-Stone-cage + rising-water variant that comes later in the Rain Dinners sequence — the room-floods-on-timer mechanic is the chapter’s load-bearing pressure-engine.
Tyrant-villain architecture-trap pattern install — Doflamingo Birdcage (Dressrosa), Big Mom Tea Party (Whole Cake), Kaido Live Floor (Wano) all share the boss-engineers-the-environment-as-the-weapon grammar that debuts here.