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 tool — breaking it without Silk Touch yields the dead grey version instead. The block needs no specific tool and breaks quickly by hand.

Brain Coral Block cannot be crafted, smelted, or used as fuel; the only source is harvesting it from ocean reefs. 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.