Idle Hack: Elements
Idle Hack (like many games) has a Elemental Type Wheel that creates rock, paper, scissors like situations. For instance, using a lot of fire damage in the Forest Mine (a Dungeon with a lot of Earth enemies) will do extra damage, but doing water damage will do less damage. Consider the below chart:

In the dungeons the elemental advantage will deal 30% more damage, the elemental disadvantage will do 60% less damage and the same element will deal 30% less damage.
Dungeon Elements
Each dungeons, expect the first one, has a random elemental type.
- Haunted Manor Physical Type Dungeon (no elemental changes)
- Desert Temple Fire Type Dungeon (60% Earth Damage Reduction, 30% Fire Damage Reduction, 30% Extra Water Damage Taken)
- Icy Castle Water Type Dungeon (60% Fire Damage Reduction, 30% Water Damage Reduction, 30% Extra Earth Damage Taken)
- Forest Mine Earth Type Dungeon (60% Water Damage Reduction, 30% Earth Damage Reduction, 30% Extra Fire Damage Taken)
- Interdimensional Rift Contains Random Enemies with Any Elemental Type