There is a single brick. That appears to be a normal brick until someone steps on it. When somebody does step on it, the brick forms a brick cube around the victim. The cube stays like this until the victim has died from dehydration or starvation. It then returns to the single brick form. When it is in the cube state, it can't be broken into or out of. Thankyou for reading my idea.
Well, to be honest, this idea seems pretty boring and generic, it does not seem to be very interesting. Here is a tip: instead of trying to think up a "kinda creature" or a "sorta object", think of a story that you want to tell, think of little moments in everyday life that make you think, and try to bring the reader to that same moment. I would recommend that you read through the available SCPs and read through the guides.
Thankyou for the advice. I'm working my way through the SCP's but there is a lot of them.
You don't have to read all of them. Also, although you could make this a lot better, there is an SCP out there that is a single brick that grows buildings, though I don't remember the number.
If you're looking to read SCPs for inspiration or know-how, I recommend reading the high-rated Series II and III articles (SCPs with numbers from 1000 to 2999), because those better represent what the site is looking for.
Also, you can read the Essays on Style, where some writers of the site talk about their personal writing processes and idea development strategies.
Odd suggestion, but what if instead of a brick cube around a person, the bricks formed a functioning crematorium complete with Chimney, and further the ashes could be mixed in with new bricks in the making to create new instances of the SCP? Not suggesting that would necessarily make a good SCP- just playing with ideas.
More generally I've noticed that there's a bit of an aversion to SCP ideas on this site that primarily consistent in "something that kills you in a squicky way and doesn't really do anything else". This is because there's been a lot of SCP's that do that, so I second the good Dr's advice.