The Monster Core

Add a block that summons a large number of monsters when activated.
There are two types of blocks: a normal one and a block that summons stronger enemies.
These blocks are wave-based and rewarded after a certain number of waves.
The rewards are better for blocks that summon stronger enemies. However, these blocks are difficult to conquer even if they are normal ones. (The number of waves and the number of enemies summoned per wave differ depending on the difficulty level.)
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And blocks that summon stronger enemies are more difficult to conquer even on "Easy" difficulty.
Also, these blocks can be made at the workbench, although the materials are very expensive. (The former block is 4 gold blocks, 4 obsidian blocks, and 1 diamond block; the latter block is 4 gold blocks, 4 purpur blocks, and the former block)
Also, there are infinite potions in this mod. (Can be created with nether star and mundane potions)
This potion can continue the wave of the aforementioned blocks until its effect wears off, and the number of enemies increases after the original last wave.