Boneworm
this creature lived on the planet Necropolis, where it fed on the bone marrow of dead bodies. The boneworms will also feed on a living being's bone marrow, if the being remained still too long. Boneworms were one of the few species which were indigenous to Necropolis, and were very plentiful. The Necropolitan reverence for their dead meant that boneworms found plenty of food in the buried bodies found in cemetaries, especially after early Necropolitans tried to exterminate them. Shortly after the Battle of Yavin, Doctor Evazan discovered that the slime of the boneworm was the missing ingredient to his own reanimation serum, and allowed him to bring recently-dead bodies back to life as zombies. Once a body was injected with the serum and interred in the Necropolis cemetary, the boneworms would begin eating at them. When the serum came into contact with their slime, the body was reanimated when the bones are drained of marrow by the boneworm and backfilled with the serum which is in the body's veins.