Here are a couple of my ideas:
- A jar that, on 1-3 week intervals, emits anywhere between a few instances and a mole of anti-protons. It must be contained in a vacuumed chamber and suspended by electromagnets to prevent antiprotons from annihilating regular matter and releasing massive amounts of energy. Released antiprotons are contained by narrowing them into a beam only a few atoms wide to destroy the antimatter in a containable manner. The jar does not react to either regular matter or the antimatter it produces, so it is thought to be extradimensional.
- A white, caucasian, 18-20 year-old male humanoid that only displays anomalous properties in a standard 25 or 50 meter pool. Upon entering, an unidentified hormone similar to adrenaline is released in the subject's body and it appears to take the form of a predatory fish, most often a great barracuda (sphyraena barracuda). I had this idea, but then saw 7475-J, and I find it too similar.
- (Potential joke scip, not likely to be done immediately, either) Shadows of any sort, which are impossible to contain. These entities may be sentient, as they take the form of their host and always place their host between themselves and the brightest source of light. Traditional public holiday include using a large rodent and its instance of the SCP to determine the length of the remaining winter. How the entity is responsible for the impact on seasonal change is under investigation.
None of these may be very good ideas, but being a youthful writer with less "real" experience, all feedback and suggestions are most welcome.