Scp-409 "The contagious crystal"
Class : keter.
Anything that makes physical contact with 409 will start to crystalize under three hours. no matter the immunity and tissue the subject has, 409 is a quartz crystal about 1.5m (5ft) tall and 0.6m (2ft) wide. The crystalization spreads by 2.5cm (1in) per minute and convert  the entire organism, inside and outside, subjects report this to be extremely painful, similair to frostbite. After complete crystalization, the organism will burst into pieces.