An endoparasitoid is a creature that lives in another during the early developmental stage of its life and ultimately kills its host.
The egg is typically deposited by the egg carrier on or in the host and upon hatching the larva begins feeding on the host gradually killing it.
In the case of the fictional Xenomorphs, the 'chestburster' larva is not known to actually feed on the host during this incubational period (though it is assumed it does, as the affected become hungry and tired) but does eventually subject it to a dramatic death. Once it's ready to move on to adulthood, the endoparasitic xenomorph will violently burst through its host's chest cavity.
In the case of the Wasp Creature, from the mockumentary series Lost Tapes, a cloud of unknown space spores enter the body of Miranda Bach. They caused a large rash to appear over 90% of her body, and chest cramps. When the creature was ready to emerge, it ripped apart her chest from the inside out. It then killed a security guard, and a doctor, before chasing another into the night. It looks like a large wasp, pitch black, with a scorpion's long tail. At the end of the episode, it shows Miranda's dead body, then it attacks the security camera.