A named threat of The South Wildlands, encountered rarely and never in numbers - real Dungeons & Dragons statistics, no auto-computed shortcuts.
Layered on top of the module's own combat AI, which still picks targets and positioning. The fight below moves through real hit-point-gated phases; every save DC and attack bonus computes from the stat block above at runtime.
Once started, a stampede runs on its own schedule, stepping toward whichever enemy is nearest at each moment it lands - not wherever they stood when it began.
Two separate stampedes can be running loose across the field at once, indifferent to what else is happening that round.
An old tread wastes nothing.
CR 25 is set against The South Wildlands's own real ambient ceiling, not auto-computed from level alone - a genuine Monstrous 25 build at 25 total levels.
Hit points (380) follow this project's own average-hit-dice convention, and every save/attack bonus derives from the ability scores above at runtime - nothing here is hardcoded past the phase gates themselves.
Boss-flagged (bypasses the drop-rate roll, two loot-generation passes) and gated to a single spawn - only one Gravemaw is ever up in The South Wildlands at a time.