* The reality of wearing a Nanosuit. While on paper, it seems like a regular powered armor suit, the truth is that it's a symbiote-like device that ''fuses'' with its user (unless you wear a protective suit that prevents its fusion like with Prophet), turning the person into a HumanoidAbomination.
* The Manhattan Virus: Infectees in their late start getting growths on their lower abdomen and pelvis, and those who die by the disease [[BodyHorror ''melt'']] [[BodyHorror into a reddish-pink goo]]. Luckily, it is not contagious.
** However, It is commented that, given its lack of contagiousness, as well as the relatively short range of the dispersal spears, the virus might be a sort of "beta" version, undergoing a controlled trial-run in New York in preparation for a worldwide dispersion of the [[FridgeHorror perfected, fully contagious product]] (which could be what the Central Park tower was meant to do).
** It's even worse in ''Crysis: Legion'', where the virus not only dissolves your body, it affects your mind as well, compelling you to find the nearest Ceph spire and literally bow down in worship and let yourself absorb more of the spore so you'll die and dissolve that much faster, and you won't even realize what's happening.
** The woman you come across in ''Seat of Power''. She's in an abandoned evac center, surrounded by rotting corpses who may have been her friends or family, blood (or something worse) dripping from her mouth, holding her dissolving internal organs in and speaking in a soft, raspy voice;
--->'''Woman''': It's nothing. I'm not that sick...I'm feeling much better now...
* One of CELL's interview subjects in ''Crysis: Legion'' is a quarantined woman who ran into Alcatraz with her daughter. The writer of the interview notes, in medical terminology, that the woman's [[EyeScream eyes have rotted away]], replaced by fleshy alien tissue that's spreading over her face and will probably kill her in a matter of hours. Even worse, because of the MindScrew effects of the virus, she can't even recognize [[spoiler:the sound of her own daughter screaming and dying down the hall, only remarking 'Oh, the screaming stopped.' with relief.]]