it will move like a snake and kill human preys.
undestructable by any means, can only be stopped by electrifying. It is too strong so that any materials cannot block it from acting.
once a human prey is suffocated to death, it will take the place of the original human vertebration. The victim's corpse will show no vital signs but it will not rot as well.
The instance so called SCP-xxx-A will be reanimated, it will then start to cover its body to hide the anomalous symptons with masks, cloaks etc, and starts to murder other human vicitims with any means. The instance shows competent skills of hand fighting and using tools like knives and machettes, just like a normal serial killer. However it will not use any guns. Once the body is damaged enough or fixed so that the instance loses the action to move, the metal vertebration will leave the instance and continue to prey a new victim.
I would also like the SCP to hide from normal humans' attention but not the foundation since it clearly understand that the foundation is awared of its exsistence and will try to do the most damage before it is contained by electrifying.
How does that sound?