Shadow(2023)

A coast guard rookie, CHANG, was on patrol when he found a tunnel. He encountered ghost in it, so he ran away in fright. WEI, the senior at the sentry post, was smoking cigarettes calmly. The lights started flashing until the power went out. During the time when they took the shift, a corpse floating on the sea brought all kinds of strange things. It seemed that some kind of force was intervening, and it became more and more out of control...