Plastination is a process used to turn biological specimens into plastic, using an unspecified technology where water and fat are replaced with polymers. This essentially turns flesh into plastic as the name suggests. It has few known uses besides preserving specimens.
Plastination yields specimens that can be touched, do not smell or decay, and even retain most properties of the original sample. The subject of plastination is first brought to light during The Specimen Case. Shogo Makishima supplies plastination resin to Kozaburo Toma and Rikako Oryo, both of whom use it to turn the bodies of their murder victims into twisted works of art.
In current times (i.e. real life), an entire plastination process can take anywhere from months to a year (many weeks at best)[1], but it did not take long for Rikako Oryo to plastinate her victims and display them, with her victims --Masami Yamaguchi, Satsuki Kuzuhara, Yoshika Okubo and Kagami Kawarazaki -- being plastinated, and Yamaguchi and Kuzuhara displayed publicly as art, in the span of two weeks. This may be due to the fact that Gu-sung Choe mentions to Rikako Oryo (after delivering plastination resin to her) that it is a special plastination resin given to Shogo Makishima by an unknown genius. The fast-acting resin did not have a patent and was newly created at the time when Shogo Makishima approached the unnamed genius and acquired it three years prior for his crimes with Kozaburo Toma.[2] Shion Karanomori also mentions that the person who created the special plastination resin "remains a mystery" to the Criminal Investigation Department even though a full investigation was done three years prior during The Specimen Case.[3]