This is a type of necromorph, its sole purpose is to spread the necromorph contagion, it is incredibly fast and agile and is capable of flight, they infect people/corpses animals etc. By lunging at them and piercing their head or back with their large strong proboscis which they then use to pump the necromorph tissue, as a part of the Process they envelop the host with their wings and afterwards they fly away. Leaving the body there to be turned into a necromorph. 