The Mad Scientist's Lab is a special production building which was released during the 2015 Halloween Event. It occurred again as a milestone reward in the 2018 Halloween Event and as a reward for one of the library quest lines in the 2019 Halloween Event.
This building offers six different production options depending on which production time the player chooses. The amount of resources produced depends on the age of the player's town when the building was earned.
The Mad Scientist's Lab cannot be motivated, and hence, can be plundered at any time when production is finished. The production of coins and supplies is affected by the town's happiness and by boosts of certain Great Buildings.
Just before the 2018 Halloween Event a new version of the Mad Scientist's Lab was introduced, increasing the amount of goods from 10 to 15 and slightly increasing the amount of coins, supplies and medals. The values of the old version can be found here.