From the Super Mario Wiki
Creepy Cavern is a cavern-based board in Mario Party 3. It is inhabited by Whomps (playing their own game of Mario Party), Thwomps, Lava Bubbles, and a Dorrie. Action Time happens when one of the players is stopped by a Thwomp and accepts its offer to ride on the mine cart for five coins. Players then have to time their jump to get on, or they miss the ride to the other side of the board. The mine carts also appear when players land on a Happening Space that is located on the tracks. In this case, Thwomp rides the cart to the other side, chasing all players in the way to that side as well. Another feature of this board is the Whomp King, who is always sleeping on a rock above the lava flow in the middle of the board. He blocks either the right path that leads upward, or the left path that eventually take players to Boo. Players can land on a Happening Space in front of him to make him turn over, but that is also achieved if a player gives him a certain item that he wants, such as a Mushroom, Poison Mushroom, Skeleton Key, etc..
In Story Mode, the human player goes up against 3 opponents and battles here to get the Courage Star Stamp.
The following table shows how many spaces there are on the board, and how many there are of a certain type.
Names in other languages