Mission Improbable

On caterpillar tracks, the mechanical alien trundled to the ocean’s edge, where a sluggish liquid flopped onto the sand, withdrew and flopped again, under a deep violet sky. The alien inserted a tube beneath the ripples. Suction commenced, accompanied by a low vibration. As the extracted liquid gurgled and slurped, the mechanical alien transmitted a message to central command: Operation progressing satisfactorily.
Unnoticed, in the glimmering darkness beyond the shoreline, a wave appeared. Unnoticed, the wave approached slowly, silently, stealthily. Unnoticed, it loomed like a predatory beast. With a dreadful, dull splash, the wave fell. When it withdrew, the sand was bare.
Central command’s communications went unanswered. It never heard from the mechanical alien again.