A plastic tiki idol is placed in the raised middle of a molded, 3d board, where it can rotate freely. Players move their explorer pawns up the sides of the mountain along paths and through caves, trying to reach the top of the mountain, retrieve the idol's giant ruby, and take it down the other side to the waiting boat. However, both the idol and volcanic vents throughout the board periodically spit out 'fireball' marbles, which physically roll down the mountain, either plowing through explorer pawns in their path, or toppling triggered bridges as they pass under them. - BoardGameGeek