The cave is a HEX location. It can be found under the lake on the school grounds. It is known for giving rare prizes. However, the cave can only be accessed weekly. It is in the Main Yard, which can be found under the "The Grounds" category. The cave appears to be a large, dark-colored stone archway consisting of chunks of rock. It leads to a tunnel enclosed by rocks on all sides. It is located next to what appears to be the posts holding up a dock. it is located in a field of seagrass, and is submerged in deep cyan water. Rays of light pierce the water and shine on the cave, giving the appearance it is not far underwater. The cave has likely been around a while, judging by the shape of its rocks.
- Either eat Gillyweed or cast the Bubble-Head Charm on yourself or equip a Muggle Underwater Breathing Apparatus
- Enter the Main Yard
- Click the image of the lake in the top right hand corner of the Yard Image
- From "The Lake" click the text "Under the Lake" just below "Hogwarts - Main Yard
- From "Under The Lake" click "The Cave"
When you have reached the cave, a button with the text reading, "Approach" will appear. If you can, click on it. Then a message will appear. Sometimes something, such as a mermaid, will block your way to the cave. Other times, you can access a prize (see below).
If you enter the cave: you will feel beneath you and pull something up from the ground. However, if you have already visited the cave that week, instead it will post a message saying, "You probably shouldn't disturb the cave too often..."