This room is where the Ancients once controlled what could be seen, or what happened in the illusion rooms.
You enter a small chamber filled with nothing but five marble podiums standing waist high, each holding a head-sized obsidian orb.
The orbs act as an interface between the Ancients and the illusion rooms. Right now, only one of the five orbs is faintly glowing, as it is the only one with a functioning room still connected to it.
When a character touches the glowing orb, read:
Suddenly, an image is projected from the orb into the airspace directly above, in front of your face. It shows a temperate forest environment. Surrounding the image are smaller images, each with a different type of environment.
If a character touches the image, it reacts. They can rotate the main image horizontally, or drag one of the smaller images over to the larger image to replace it with the new environment. This changes the apparent environment of Room 18. If another character is in Room 18 at the time, any characters here can see what that character is doing.
17. Dining Hall
This large room was once where a large number of Ancients could eat their meals. Stone tables and tall buckets filled with decomposing refuse are scattered throughout the chamber.
Bar. A long window with a flat, marble surface below it allows one in the larger section of the chamber to see into the smaller section, and vice versa. A character can easily climb through to the other side, though if they are in combat they will need to make a DC 10 Dexterity (Acrobatics) check to do so while moving.
Cooling Room. The steel door leading into this side room has the image of a snow flake on it. A DC 10 Wisdom (Insight) check reveals that it means the room beyond was designed to keep things cold. Opening the door releases two ochre jellies created from centuries worth of rotting food now turned ooze. The character that opened the door also needs to make a DC 15 Constitution saving throw or they are poisoned for 1 hour.
Tall Buckets. Any character standing next to one of these trash receptacles needs to make a DC 10 Constitution saving throw or else succumb to the poison condition for 1 hour.
18. Room of Illusory Environments
This room is specially crafted to trick creatures into thinking they are in the environment that it represents. If the environment has not been changed in Room 16, then the environment is that of a temperate forest.
Upon initially entering the room, characters may think they have stepped into a portal to the outside. However, it is all merely an illusion that a character can see through with a DC 25 Wisdom (Insight) check. There are no animals, though background animal noises can be heard. There are no materials that can be foraged either. Anything stripped from a plant disappears, and the plant reappears as normal back where it came from.
If the door is not propped open, it closes behind the characters. The nature of the illusion allows the room to seem unending, using visual stimuli and unnoticed nudges of force. If walking together, changes to the environment are minimal. However, if the characters separate from each other by 30 feet, they can find the walls of the room and eventually the door which can swing either in or out. Damaging a known wall by weapon or spell creates a permanent mark to the wall that seems to float in the air.