Evil Alchemist's Lab infested by Burrow Spiders (clone)
The Alchemist Tog Ver Sharog made a deal with the his neighbour, the temple of (evil god) to create this lab. There was a great demand for rare ingredients for potions and poisons. The business was very profitable until the day when the Burrow Spiders broke into the lab. Now the lab if full of spiders, a ghost of an alchemist, his undead mutated apprentices and other things that evolved from what was left of alchemist experiments.