GoldenPlaysTerraria
Steampunker
The Lunatic Cultist is one of the few bosses with a treasure bag but no way to obtain it. I think an endless mana pouch would be fit for his treasure bag. He uses magic attacks and never seems to run out. The endless mana pouch would eliminate mana sickness and the need to make mana potions. Since the Lunatic Cultist is almost endgame it would not be very overpowered. It would be a blue tied pouch and would take up an accessory slot unlike the endless musket pouch and the endless quiver.