There are 4 skulls on the 5th Floor of the Witch's House.
The Skulls are needed for you to proceed in the game. You must find the 4 skulls to get the Water Flowing in the Water Chamber. They are located at;
- In the big pot in the hallway on the way to the Skull Room
- In a shelf in the Poisonus room. (You need to get writh of The Greenery first)
- Under the desk beside the bed in the Yellow Flower Room
- After you have talked to the Red Grass, one skull will appear on the chair behind the book about the Talkative Plants.
After you have gotten them all, you need to place them so they face the correct way in the Skull Room. The one placed Top Left shall face forward, Top Right shall also face forward, Bottom Left shall face Left and Bottom Right Shall face Right. If you have done it correct then you can pull the lever and water will appear in the water chamber, you need water to proceed 2 steps later on in the game. If you have done it wrong then pulling the lever won't work.
In Extra Mode, all the skulls are already placed so you just need to pull the lever.
After you have pulled the lever and leaving the room, a Giant Skull will appear so you need to run.