Credit:
The idea is not made by me. It is taken from https://www.reddit.com/r/minecraftsuggestions/comments/87o0db/ghast_skin/
This mod adds a set of new armour and a new material.
When you kill a ghast, it has a chance to drop a piece of ghast skin. It is a thick white leathery substance that can be crafted into ghast skin armor. Ghast skin armor offers the same protection as leather armor, but it has one major advantage over leather armor.
If you wear a full set of ghast skin armor, you will be provided with immunity to fire and lava. Thanks to the ghast skin, you will be able to explore the Nether a lot more easily. If you only wear partial ghast skin, then it will give you some resistance to fire, but not immunity. You can also brew ghast skin as an alternate way to get fire resistance potions.
This is very balanced because of the armor's low protection and durability. You would be at a very high risk of being killed by the mobs in the Nether.
Screenshots:


