Brain Coral Block is a pink, brain-textured coral block that generates naturally on coral reefs in warm ocean biomes, added in the 1.13 Update Aquatic. It is one of five coral block colours — brain (pink), tube (blue), bubble (purple), fire (red), and horn (yellow) — and is named for its lumpy, convoluted surface that resembles a mammalian brain.

A Brain Coral Block stays alive only while it touches water. Place it on dry land or remove the water beside it and within a few seconds it converts into a grey Dead Brain Coral Block; this change is permanent and cannot be reversed. To collect a living block you must mine it with a Silk Touch pickaxe — breaking it with a pickaxe without Silk Touch yields the dead grey version instead. Brain Coral Block requires a pickaxe to mine: broken by hand or with the wrong tool it drops nothing.

Brain Coral Block cannot be crafted, smelted, or used as fuel; the only renewable source besides harvesting ocean reefs is the wandering trader, who sometimes sells a random coral block for 3 emeralds. Builders prize it for aquariums, underwater bases, and reef dioramas, often placing a water source beside it so the surrounding water stays in contact and the coral never dies.