Sulfur Cube is a bucketable jumping mob that spawns exclusively within sulfur caves. It exists in two distinct sizes — large and small — each behaving quite differently from the other. When a large Sulfur Cube is defeated, it splits into two small versions that gradually mature into full-sized adults over the course of roughly 20 minutes, similar in growth behavior to baby mobs. If a large Sulfur Cube has been given a name tag, that name carries over to both small cubes produced upon its death.
The most distinctive trait of the large Sulfur Cube is its capacity to absorb whole blocks — either picked up from the ground nearby or handed to it directly by a player. Once a block is absorbed, the cube becomes stationary and the block remains visible inside its body. More notably, the absorbed material fundamentally reshapes how the cube behaves physically: wool causes it to become floaty, blue ice makes it slide rapidly, soul sand grants it significant knockback resistance, and TNT enables it to ignite and detonate. The absorbed block can be reclaimed using shears or by killing the mob. Large Sulfur Cube can also be captured in a bucket, creating a bucket of sulfur cube.
Small Sulfur Cube cannot absorb blocks and are neither bucketable nor leashable. They can be tempted and fed slimeballs to shorten their remaining growth time. Feeding a small Sulfur Cube a golden dandelion halts its development, keeping it from maturing into a large version.
While the Sulfur Cube does not attack on its own, certain absorbed blocks introduce indirect hazards — a magma block deals 1 HP of damage to nearby entities, and an absorbed TNT block enables explosive behavior. Upon death, a large Sulfur Cube drops its absorbed block along with 1–2 experience points. Small Sulfur Cube drop nothing and do not split further when killed.