- "Please... K- Kill me!"
- ―Mary (from Aliens)
Mary was one of the Hadley's Hope colonists on Acheron. She was one of the last colonists to be taken by the Xenomorphs, and was actually alive when the Colonial Marines discovered her, but she perished soon afterwards when the Chestburster inside her hatched.
Mary was one of the colonists taken to the Hive inside the Hadley's Hope Atmosphere Processing Plant, and the only one still alive when the Colonial Marines under Lieutenant Gorman's command arrived. She was tended to by Corporal Dietrich, despite pleading with the Hospital Corpsman to kill her; the Marines had thus far had no experience with the Xenomorph species and were unaware of the fate that awaited Mary, otherwise they may have complied. She began convulsing almost immediately and was killed moments later when the Chestburster insider her erupted from her chest. Sergeant Apone and Corporal Dietrich immediately torched the creature, and Mary's body, with M240 Incinerator Units.
- The character is not named in the film and is listed in the credits as "Cocooned woman".
- To create the effect of the Chestburster bursting out of Mary's body, the actress wore a prosthetic chest piece made of foam through which the Chestburster model emerged. A replica dummy of actress Barbara Coles was then used for shots where the Marines torched her body.
- Mary is the only Hadley's Hope colonist to be killed on-screen.