The concept:
Elevator Pitch: SCP-XXXX is a tall, malnourished, humanoid being with a split down the middle of it's face and black claws up to two metres long. It shows signs of telekinesis, and can open instances of SCP-XXXX-1, a pocket dimension with only a blue tunnel that loops around.
SCP-XXXX traps it's victims in SCP-XXXX-1, skins them, makes them floats to the ceiling in agony and then creates a time loop, allowing the previous victims watch themselves die forever.*
The effects here feel quite disjointed, as there doesn't seem to be any reason why the skip can do these things. The telekinesis and pocket dimension are the most prominent examples of this, neither of these two effects relate back to each other, the story or the skip. Which in tern, makes them feel necessary and out of place. -One major effect should be enough, having too many major effects can cause the skip to feel op, or cause the focus to be lost. I would recommend you chose one major effect, and make that the focus, try thinking about how the Foundation would interact with it and how this would affect the skip itself.
On top of that, the effects are really the only thing given any attention, I don't have any insight into its history, motives or the Foundations interactions with it, this more or less just feels like your run of the mill murder monster. As there doesn't seem to be much behind it, If I took the "dangerous" aspect, away from the skip then it would just be a grotesque looking humanoid with odd effects that imo, don't match up. I would recommend you try looking more into the skip itself, what gives it an edge? what makes it different? what makes it interesting/attention grabbing?
The narrative
Central Narrative: Exploration Log
This is too vague for me to critique, there isn't any outline of a narrative or basic idea of what you want to do here. Exploration logs can be apart of a story, though they themselves cannot carry an article/story alone. There isn't much of setup here, as the story starts after the Foundation has discovered the skip, been around it long enough to know it creates pocket dimensions and has already found a reason to send people in. The payoff also isn't given much time, as there doesn't seem to be anything learnt from the exploration, what doe the Foundation end up doing in the end. overall, I'm not sure why its being explored? what happens in this exploration and how that affects the Foundations understanding/interactions with the skip.
Red or green?
Due to my afore mentioned concerns, no Greenlight.
If you would like me to give this further advice/feedback, then feel welcome to shoot me a PM or ask via IRC. response times generally range from 2-12 hours over PMs. If your looking for additional critiques in general, then I couldn't recommend the Butterfly squad more:)