They come from a leathery, egg-like object
Covered by a blueish layer of moist and warm mist
A strange organic parasite shooting out
Hugging your face and wrapping it's long tail around your chest
Irremovable and if cut, it's bleeding acid
Implanting an embryo, through your mouth, in your chest
Now you are the host, incubating parasite offspring
When strong enough, cracking your chest and jumping out

Growing up fast and casting it's skin off, several times
Fully grown now and ugly like hell
Having no eyes but a double set of teeth
A long tail to rip you apart
When opening it's mouth, showing you it's teeth, an extra pair shoots out

Taking a bite from your skull
Killing all life form

Whether it's to eliminate, or to incubate the queens eggs