My idea is a dark blurry humanoid figure, with the voice of a little kid. It will try and interact with people and become friends with them. If it makes a friend, it will ask them questions and slowly collect information on them. When it knows enough, it will seamlessly replace them, looking and sounding exactly like they do. It discards its victims bodies within 100 meters of where they met, and the victim is missing their eyes, teeth, and vital organs. Additionally, it's found with many of their possessions, the SCP reasoning that they would like to have them.
If people begin to become suspicious of the SCP not being its victim, it will become very stressed and act odd, like never sleeping or eating, or laughing for no reason. If it's discovered to be a fake, it will begin to blur similarly to how it is before its killed its victim, and will overall lose form, as if it's melting. Anyone viewing this process will begin to quickly suffer from severe brain damage, the wounds looking as if they were burned, or even scooped off. It will then disappear and will return to its residing location (its containment cell, although it's original home was a forest).
There will be a section on its recovery, where a foundation doctor's daughter becomes a victim of the SCP. It replaced her for about three months, until early September when the girl was supposed to start third grade. The SCP was discovered when in class, it had absolutely no idea how to do multiplication, getting extremely flustered, lashing out at people, and eventually lost form when the teacher called the police.
Is this idea good? Please give me any advice you can think of, or even just a basic opinion. Thanks for reading my long post!