The decayed altar is a regular altar found in level 33 Wilderness. It is inside a huge cave, and players must crawl through small openings to get to the actual altar. Prior to starting the Summer's End quest, there are no monsters or hazards, just a lot of empty space. However, after the quest, this is where the level 785 Corporeal Beast resides.
North of the farm ruins, there is a three-part cave with the bodies of the spirits buried at the end with an altar.
- In the altar's room, there are several gravestones. Examining them gives the names of the NPCs (minus the Spirit Beast's name) in the Spirit of Summer quest, including a grave for Summer herself. This cave is actually their burial grounds.
- There are patches of soft soil in the cave, but digging near them with a spade seems to have no effect (players cannot walk on top of them).
- Despite the fact that the altar is decayed, it can still be prayed at.
- There are also remains of fires in the cave, indicating that the caves were used at some time in the past.
- All the graves are made of wood planks, very much like a player's default grave, except for Jennica Bonde's grave. Hers is made of stone, and the only one that a player is able to read fully.
- If you look east of the eastern walls, the Tower of Life basement comes into view, and if you look west of the western walls, you can see a tower of some sort surrounded by a swampy area.