From The Fog Herobrine

Herobrine is rendered as a Steve-like figure with blank, glowing white eyes, faithful to the classic creepypasta look. He behaves like an intelligent presence that studies you, alters your world, and reveals himself on his own schedule, rather than a normal monster that spawns and rushes in. The effect is strongest when you play blind and at night, in a long survival world where the sense of being watched can grow naturally over many sessions.