The Queen Leech is a enemy from the Resident Evil series. It was a giant humanoid mound of sentient leeches and the final boss of Resident Evil 0. It started the game inhabiting the body of a newly-youthful James Marcus and had control over all other leeches in the Training Facility.
In its first form, the Queen Leech attacks by hitting, grabbing, or throwing the player. After enough damage is given, it mutates slightly, giving it more attack power and defense. After more damage, it is rendered unconscious and gives up the silver and gold keys that open the blast doors covering the emergency exit shaft.
The Queen Leech has a second form in which it becomes a massive green creature with multiple tentacles and a flower-like organ on its back which continually secretes acid. In that form, it has two main attacks, in which it rams the player character and spews acid from the flower. It is also invulnerable to all weapons and can only be killed by opening the four emergency helipad shutters. This lets in sunlight, whose ultraviolet radiation passes through its cells, burning them with a high degree of proficiency, making it highly unsuitable for general use as a biological weapon. Upon the sunlight consuming its body, it was terminated by Billy Coen.
- The Queen Leech featured in Resident Evil: The Umbrella Chronicles as a boss.