It's a Bug Hunt by Egantx7

Question 4

The creature's life cycle can be described as: a queen lays an egg, which in turn hatches a "BLANK", which attaches itself to an organism and implants an embryo inside that organism. That organism dies when the grown embryo bursts out of their body.

What is the term that should be inserted into the blank, which references the part of the body that this stage of the alien's life cycle "embraces" during attachment.