Sculk Catalyst is a reactive block found in the deep dark biome or dropped by wardens. Its main function is to spread sculk when a nearby mob or player dies and would have dropped experience. Upon detecting such a death, the catalyst “blooms,” emitting soul-like particles and converting surrounding blocks into sculk blocks, sculk veins, and occasionally sculk sensors or shriekers.

This process, known as sculk growth, replaces natural blocks like stone, dirt, deepslate, and more with sculk-related blocks. Each experience point becomes a sculk charge, which powers the conversion. Sensors appear 9% of the time and shriekers 1%, though shriekers made this way can't summon wardens.

Sculk catalysts emit a faint light level of 6 and have a glowing, animated texture. They can only be harvested using Silk Touch—otherwise, they drop 5 XP. Hoes are the fastest tool for mining them. Beyond their utility in automated sculk farms or XP-based contraptions, they also serve as eerie, reactive centerpiece blocks in deep dark or mystical-themed builds.