刻印虫
Insects seen in the [[fate (series)|Fate series]], which incubate in their host and grant them the ability to use magic at the cost of shortening their lifespan. Appeared [[phallic symbol|extremely phallic]] in the original release of [[Fate/stay night]], but was edited for the Realta Nua release and anime adaptations.

[[Matou Kariya]] uses an evolved form of the crest worms, blade wing worms, in combat.
crest worm