At the top there's a list of the different ideas, and below that is my attempt at writing the fourth. Hope you enjoy them.
1. We've already got a reality-warper or two who can do something like this. SCP-239, anyone?
2. Interesting… you'd have to flesh it out a lot more, of course. Does it have to be clockwork? We've got a lot of clockworks.
3. So, it changes the state of matter in such a way as to blatantly break the laws of thermodynamics? That might be worth writing up in more detail.
4. The idea of an object somehow taking up negative mass/volume is interesting in a paradoxical sort of way. The idea of a person or object spontaneously vanishing, leaving a black silhouette behind, is a little bit boring by itself. I'm not really enthralled by what you've already written.
1. Maybe take out the "he thinks it's a monster so it turns into one" power and instead just focus on the monsters under his bed and in his closet?
2. I thought it would've been made sometime in the Victorian era, so clockwork and steam would've been the best choices to power the thing. That, and there's the obvious clockwork-time relationship, though I think I could be able to change it and still keep that, some how.
3. Yeah, I can't think of anything to reply to that. I'll try and write out the SCP.
4. I was trying to put the focus more on the negative space part than people vanishing, which I put mainly because I wanted a shape besides a plain old sphere. Maybe if I changed it to just one in a remote location without anything about people vanishing? Or change it into a random ripped shape like a hole that was actually "torn" out of the world.
1. We've got a monster-producing closet, too.
2. Well, if it's LATE Victorian era, it could be gas-powered.
4. Well, that brings up a question: what would negative space look like? Do keep in mind that negative (meaning less than zero) space is not the same thing as a hole in space. Even a black hole has mass and volume, after all. It's probably a good idea not to have it be a commonly occurring phenomenon, in any case.
1. Huh. Well then scratch that idea.
4. When I used negative space I wasn't actually referring to it as negative. I was talking more about it being used in art, like those illusions that could be either faces or goblets depending on the way you look at them. Thinking back on it the term doesn't really fit it all that well. The things themselves are supposed to be the complete absence of anything. I thought of it as looking like it was colored pitch black, but actually being dark because there was nothing in the "hole", even light. Thinking about this now, there's a lot of problems I hadn't thought of before, so it's going to have to be rewritten if not scrapped entirely.