human
Write a detailed description of a foreboding scene inside a cave cavern with a lake.
assistant
It could be just an illusion, but a sinuous serpent-like shape the size of a large schooner circles the waters near the shore. The distance to the lake and the distracting reflection of the water's surface makes it difficult to pinpoint the oddity, but whatever it is, it continues to surface and descend into the sea of this cavern with alarming regularity.