Okay so the first idea I have is that you could have to go hunt down a Giant. This giant would be an extremely rare mob (just a couple at any one time per world), and you would obtain a special gem from it. So far the only idea I have is that this could be a ruby that is dropped from the giant when you destroy it. The ruby drop would not be affected by looting like a Nether star.
The giant would be around 5 blocks tall and maybe 2 blocks wide. The giant could have a large club that it would swing at the player. It could have 75 hearts of health, and could do 8-10 full hearts of damage per hit. They would also have a 50% resistance to ranged attacks and would be vulnerable to the fire effect.
The giant would be around 5 blocks tall and maybe 2 blocks wide. The giant could have a large club that it would swing at the player. It could have 75 hearts of health, and could do 8-10 full hearts of damage per hit. They would also have a 50% resistance to ranged attacks and would be vulnerable to the fire effect.