Editing Xenomorph (section)

====Chestburster====
[[File:Alien 1979 Chestburster.png|thumb|left|A chestburster emerging from Kane's chest in ''Alien'']]
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After impregnation, facehuggers die and the embryo's host wakes up afterward, showing no considerable outward negative symptoms and a degree of [[amnesia]] regarding events at the time of implantation. Symptoms build acutely after detachment of the facehugger, the most common being sore throat, slight [[nausea]], increased congestion, and moderate to extreme hunger.<ref name="A1"/> In later stages where the [[incubation period]] is extended in preparation of a queen birth, symptoms will include a shortness of breath, exhaustion, and [[hemorrhaging]] (detectable through biological scanners and present in nosebleeds or other seemingly random bleeding incidents), as well as chest pains caused by a lack of space due to the chestburster's presence or even premature attempts to escape the host.

The incubating embryo [[Horizontal gene transfer|takes on some of the host's]] [[DNA]] or [[Phenotypic trait|traits]], such as [[bipedalism]], [[quadrupedalism]],<ref name="A3" /> possessing the [[mandible]]s of a [[Predator (alien)|Predator]],<ref name="AvP-R">{{Cite AV media|people=[[Shane Salerno]] (writer) [[Brothers Strause|Colin and Greg Strause]] (directors)|title=[[Aliens vs. Predator: Requiem]] |medium=DVD |publisher=[[20th Century Fox]] |date=2008}}</ref> and other structural changes that enable adaptation to its new environment. According to Weyland-Yutani medical scientists in ''Aliens: Colonial Marines'', the chestburster will draw nutrients from the host's body in order to develop a placenta as it grows, attaching itself to several major organs in the process. The placenta has cancerous qualities, such that even if the embryo were removed surgically, the placenta would simply cause the affected organs to shut down, resulting in death; the only exceptions to this are from human-xenomorph hybrid hosts like the cloned Ripley 8, who survived an extraction procedure without issue.

Over the course of one to twenty-four hours--indeterminable in some cases, and sometimes up to a week, in the case of some queens--the embryo develops into a chestburster, at which point it emerges, violently and fatally ripping open the chest of the host.

There is no on-screen explanation of the reasons for the different incubation times. Fully-grown aliens may avoid harming species acting as hosts for un-emerged chestbursters, though this may only be in the case of a queen embryo.

When a chestburster erupts from the body of a human host, it is less than {{convert|30|cm|in}} tall, although the embryo can vary in size from a guinea pig to a large dog depending on the size and species of the host. Its appearance and adaptive characteristics are also determined by the host. Typically, its first instinct upon emerging is to flee and hide until full maturation, as well as find a source of nutrition. However, it soon undergoes a dramatic growth spurt, reaching adult size in a matter of hours; in ''Alien'', the chestburster had grown to {{convert|2|m|ft}} in height by the time the ''Nostromo'' crew located it again.{{efn|In ''Aliens'', Ripley claims that the creature killed the entire crew in 24 hours, so the growth stage must be under one day}} The chestburster is shown to have molted before reaching maturity.<ref name="A1"/> In ''Aliens vs. Predator: Requiem'', Alien warriors who are still growing are shown, displaying shed skin. In the unrated cut, the [[#Predalien|Predalien]] is shown wiping off its final molted skin at the film's start.

The chestburster was designed by ''[[Alien (film)|Alien]]'' director [[Ridley Scott]] and constructed by special effects artist [[Roger Dicken]].<ref name="woman">{{cite book |last1=Gallardo |first1=Ximena |date=2006 |title=Alien Woman: the Making of Lt Ellen Ripley |pages=25 |publisher=A&C Black |isbn=9780826415707 |url=https://books.google.com/books?id=4ecFu4B_CpoC&dq=chestburster+roger+dicken&pg=PA25}}</ref> Giger had produced a model of a chestburster that resembled a "degenerate plucked turkey"<ref>Giger p. 56</ref> and was far too large to fit inside a ribcage. Much to Giger's dismay, his model reduced the production team to fits of laughter on sight. Scott drafted a series of alternative designs for the chestburster based on the philosophy of working "back [from the adult] to the child" and ultimately produced "something phallic".<ref name="burster">''Alien Evolution'', in the [[Alien Quadrilogy]] box set</ref> The chestburster in the original ''Alien'' was armless, but arms were added in ''Aliens'' to facilitate the creature crawling its way out of its host's corpse.<ref name="Winston">{{cite book|author=Jody Duncan|author2=James Cameron|name-list-style=amp|title=The Winston Effect: The Art and History of Stan Winston Studio|date=2007|page=336|isbn=978-1-84576-150-9|publisher=Titan|location=London}}</ref> This concept would be abandoned in ''Alien Resurrection'', but it would return in ''Alien: Covenant''.