1. An old-timey camera that functions as a normal camera, except that when its used to take photograph an animate creature, that creature vanishes after 48 hours. Following the vanishing, creatures exactly identical to the vanished creature are spotted here and there in the world. This is of course harder to verify when taking a picture of, say, a pigeon, but humans are more easily distinguished from one another. Research into the doppelgangers (or subjects themselves, I don't know yet) is underway.
2. A creature found in the subway in Sweden. It looks like a human but is extremely thin and feral, violent and very sensitive to light. Understands human speech but has a very limited vocabulary and isn't very intelligent.
Neither idea is very interesting on its own but I'm in the process of writing a lot of experiment logs for each one of them. I think number 2 is very uninteresting and generic, I feel like it needs a twist instead of just being a scary boogeyman. Number 1 has some merit I think, if I come up with a good idea for what happens to the vanished people.
What do you all think? Advice, criticism and ideas most welcome.
I have rough drafts written up on them in my sandbox: http://scpsandbox2.wikidot.com/ixias The camera is SCP-1735, the tunnel creature is SCP-1125, with experiments for both found in the corresponding addendum. The numbers are probably taken, I just put something down so I didn't have to work with SCP-XXXX, SCP-YYYY and SCP-ZZZZ.