Second Life - Mean Streets
It's latex, but it's not
It came from the latex-like suit that covered Aria Warden from the neck down. Using ingenuity and a strict adherence to the scientific method, Molly and Rebekkah were able to get a sample off the suit for study.
It seemed to be alive, with a powerful drive for self preservation and protecting the host. While encased in it Aria experienced near super human strength and reflexes. She also ate and drank four times what she normally did and excreted no waste.
When she encountered the man who identified himself as Dr. Vashir he seemed able to control it through force of will. Extending it up over her mouth to gag her and restraining her with it.
When she was freed from it the material seemed to evaporate completely. The only remaining sample is in the custody of Molly and Rebekkah.