human
Make a concise location description of a spooky scene inside a tunnel cavern with a mass and a portal.
assistant
A horrible sarcous substance clings to the stone walls in places, weeping yellowish fluid that smells of copper and sickness. Whatever it is, the material is raw and pinkish like fresh-scraped flesh. Strings of it drip from the ceiling like a horrendous parody of hanging vines. It culminates in a tumorous mass along the far wall, taking the form of a quivering pinkish portal suffused with bilious green light.