Desert Convoy Flees Colossal Walking Entity

the prompt

Massive sci-fi desert world at sunset.
A convoy of armored vehicles crossing endless dunes beneath giant twin moons.
One traveler notices something impossible on the horizon: a gigantic mountain slowly moving.
At first everyone thinks it is a sandstorm illusion. Then the mountain changes direction.
The caravan begins accelerating desperately.
Visible danger escalates: dunes collapsing from distant impacts, enormous dust clouds approaching,  seismic vibrations shaking vehicles, giant footprints appearing in the desert behind them.
As night falls: the moving mountain becomes clearer.
It is a colossal walking structure crossing the desert:
part creature, part machine.
Entire villages disappear beneath its legs in the distance.
The convoy races through narrow canyons while behind them: the gigantic silhouette advances across the dunes under moonlight.
At climax, the colossal entity steps directly over the canyon ridge behind the convoy. Its massive glowing body blocks the sky.
Then suddenly, it continues walking past them into the darkness.
Ultra cinematic sci-fi epic, giant creature scale, desert atmosphere, realistic dust physics, grounded survival tension, massive environmental visuals.