Experimenting on the clock

At base1[redacted] we have caught a dark one alive

condition: extreme aggression towards staff

age: n/a

sex n/a

eye color: crimson

misc: patient seems to be crying blood

hair: none

AFTER AUTOPSY: found human flesh in digestive tract but it seems like they dont eat humans for nutrients after extensive search we have found a dark red parasite lodged near the brain stem after removal subject has died

no further subjects at this time

personal note: these things used to be humans what in the world could cause such changes in so little time?