Betweenlands: a strange name for a strange place. This mod adds an entirely new dimension to the game - in a similar vein to old mods like Aether - but this place is not peaceful, pleasant, or for the faint of heart. Loads of things are out to kill you, including the environment itself. The air is so foul that any creature breathing it slowly decays. The realm has no day/night cycle. Clocks, maps, redstone, flint and steel, and compasses are useless here. Due to the warm and wet environment of The Betweenlands, food from other dimensions rots when traveling through the portal to this dimension, becoming Rotten Food.
As Flint and Steel cannot operate in the dimension, there is an alternative way to creating a fire. Simply hold right-click Moss, Cave Moss, or Thorns (either placed or dropped, both block and item forms work) with an Octine Ingot to light it on fire. The ingot will cause the plant to slowly build up flame until it turns into a fire block, without consuming the ingot in the process. This is essential for getting an Infuser started.
Torches will not work here, and you will require Sulfur Torches instead. Along with that, tools from other dimensions will be diminished in effectiveness in the Betweenlands, prompting the player to use the Betweenlands tools. However, Betweenlands tools in your inventory will undergo Corrosion.
If you think a bigger challenge is needed in Minecraft, Betweenlands will definitely scratch that itch, while providing some interesting new lore and content.
Betweenlands is for version 1.7.10. You can download it right here. Enjoy!