The Calamity Mod is a large content mod for Terraria which adds many hours of endgame content and dozens of enemies and bosses dispersed throughout the vanilla game's progression. The Calamity Mod also features several harder difficulty modes, five new biomes and new structures, a new class, a new leveling mechanic, more than thirty new songs, over fifty recipes for previously uncraftable vanilla items and other assorted changes to vanilla gameplay.