Queens produce a thick, protein-based substance that stimulates cellular growth, which they are able to expel in liquid form. When the Queen covers the wounds of a Zerg creature or nest structure with this reddish fluid, the damaged tissue regenerates in a matter of seconds. Conversely, if the fluid is combined with a catalyst secreted by a gland on the Queens neckwhich gives it a sickly green colorationand forcefully injected into the hatchery, the structure will rapidly incubate new Larvae.