From the Super Mario Wiki
Castle Koopula is a large, imposing castle owned by Count Koopula in The Super Mario Bros. Super Show! episode "Count Koopula". Located in Turtlevania, Castle Koopula, from the outside, has a resemblance to a spider, with large, leg-like protrusions coming from its sides.
On the inside, Castle Koopula has many winding corridors, large rooms and secret passageways leading to different parts of the castle. In the cellar of Castle Koopula is a storage room where tomato sauce and laundry is help; beneath this cellar is a sub-basement where Count Koopula's zombiefied Goomba minions create tomato sauce. A torture chamber, referred to as "Count Koopula's Torture Chamber, Wax Museum and Dungeon of Horrors" is also located in Castle Koopula, having such devices as a stretching rack, tickling machine and a faucet that continuously pours water and the face of a victim. After his defeat, Count Koopula abandoned Castle Koopula, which began to crumble and eventually collapsed after Count Koopula left it.