Blocks

Blackstone Pedestal

Right clicking this block with the Shard of Uncertainty (which is dropped by the Wither boss), will summon the Monarch of Chaos boss. Right clicking it with the Withered Demon Heart will summon the Decaying King boss.

Crimson Obsidion

Chungus Monolith

When placed in forests, enables Moderately Sized Chungusus to spawn within 32 block radius.

Moonstone Ore & Block of Moonstone

Found on diamond level. In 1.19.2 and under, the level and ratio of ores spawning can be changed in config. In 1.20.1 and above, the ores spawn with datapacks, so there are no config lines that regulate spawning for those versions. Instead, make a custom datapack that changes the spawning if you want to change it.

Old Moon Altar

Right clicking this block with a Lost Soul will summon The Returning Knight boss fight, or the Fallen Icon if the Essence of Eventide was used (dropped by Frenzied Shade). If right clicked by the Draugr sword, it will summon the Old Champion's Remains boss, without consuming the sword.

Soul Infused Blackstone Block

Soulfire Lamp

Can be turned on and off by right clicking the block with a Lost Soul in hand.

Soulfire Stain Block

Has the same functionality as Magma blocks.

Verglas Ore & Verglas Block

Verglas is a rare and delicate ore, said to contain the very essence of winter and spring. As of update 0.9.8.2, Verglas ore can be found anywhere between Y level 120 and -63 in very small amounts. For earlier version however, they can be found in mountain biomes only between Y level 100 and -60 and are just as rare as emeralds.

Just like Moonstone Ore, in 1.19.2 and under, the level and ratio of ores spawning can be changed in config. In 1.20.1 and above, the ores spawn with datapacks, so there are no config lines that regulate spawning for those versions. Instead, make a custom datapack that changes the spawning if you want to change it.

Withered Grass, Dirt and Flowers

Will apply Decay status effect to any entity that steps on it or collides with it.

Hydrangea & Oleander

After flowers have been withered, these two types will replace them. After some time, they will turn back into a completely random flower, based on whether it was tall or not. If broken down, picked up and the placed by the player, they will not turn into a normal flower. They can be brewed into Potions of Magical Warding, Tainted Ambrosia (applying Cursed Wounds) or crafted to colored dye.

Items

Arkenstone

Dropped by the Returning Knight or Fallen Icon upon their defeat.

Big Chungus Music Disc

Crafted with 9 Chungus Emeralds, dropped by Moderately Sized Chungus. Will play the Big Chungus Theme Song by Endigo.

Chaos Orb

All the colors of light and dark pass through this orb. Throw it into the sky to summon Day Stalker & Night Prowler.

Crimson Ingots, Demon Hearts and Demonite Chunks

Crafted by combining and smelting Demon Hearts.

Essence of Eventide & Essence of Luminescence

Essence of Eventide is dropped by the Frenzied Shade. Essence of Luminescence is dropped by the Fallen Icon.

Iron Skull

Used in the Old Moon Altar recipe.

Lost Soul

Lunar Ring

Using this ring will grant the Lunar Herald status effect.

Moonstone Compass

Points to the closest Decaying Kingdom in the Nether or Champion's Graves structures in the overworld.

Moonstone & Verglas

Gathered by mining the ores.

Moonstone Tools

Crafted with Moonstone and a single piece of Verglas. Has better efficiency than Diamond, but Netherite is still superior.

Soul Ingots

Skofnung Stone

Using it will remove all bad effects and empower the Skofnung sword if in hand.

Silver Bullets

Used by Gun items. Crafting with iron produces less bullets compared to crafting with Silver Ingots from any mod.

Shard of Uncertainty

Dropped by the Wither boss. Used to summon the Monarch of Chaos boss fight by right clicking the Blackstone Pedestal with it.

Withered Demon Heart

Used to summon the Decaying King if used on Blackstone Pedestal.