Darkness's Laboratory is a science lab featuring a potion where different color combinations produces side effects for Sam - including making him invisible for a short time. It also features the dumbwaiter which Sam can ride to the kitchen (if it is on this floor). It also sometimes features a sock.
Sam will turn visible again if the player waits too long or if Sam enters the following locations:
- Returning back to potion counter
- Exiting through the door outside the Lab
- Returning back to the kitchen
- Trying to Exit Darkness's House down the ropes
- Going upstairs to the Doors of Knowledge