Marlin's cave is located in a place in Rock Bottom called the Zone of Perfect Weather (where it never rains even a drop). It is shaped like a giant wizard hat with crescents and stars on it with a small card house for the entrance. Inside, it has an entrance room with a slot machine where, under certain conditions, opens the way to a path to a dark, cold, wet maze with 3 4-way parts, which can be easy to get lost in. Progressing through that leads to a tower of sorts, where Marlin is upstairs in his Wizard Lair full of books and potions, and Patrick is downstairs, sleeping in Marlin's hammock.
- The Skull Rock (which appears in Scaredy Pants) appears where the sign that says "Marlin's Cave" is.