"Those who are captured by the amalgamate are oftentimes not killed. As it turns out, the amalgamate cannot take advantage of the minds of those it consume if they are dead, or at least what they will be able to retrieve from those minds is greatly reduced. Therefore the amalgamate often keeps their victims alive as long as they can during the assimilation process. This is why inside amalgamate hives one can often see these sort of pods or cocoons that keep the host alive for several hours while the amalgamate scours their mind for anything important or interesting, discarding everything it doesn't need."

Higher-res: https://sta.sh/01i8cbvs3rvo