I don't think yet that I want to write it up, but I had a dream last night and I think it could work well as an SCP.
It involved a colony of white fruit-fly like insects that survive by eating the caloric "value" of matter, rather than eating it directly. Anything the insects do this to, loses its ability to be metabolized properly, and would also die (if alive) due to becoming completely chemically inert. The cells in the foodstuff become anti-metabolic. This would also mean they can't decompose.
A pizza, zero calories.
A person, Zero calories.
The subject would die, becoming chemically inert. It would stop all life processes in the body, and even stop the decay process. If the cells can't chemically be altered, then they'll be static and unchanging. No decomp.
