Alright, time to propose an idea for my first SCP!
SCP-XXXX is comprised of two entities: an incorporeal presence (SCP-XXXX-1) and a man in his late 20s (SCP-XXXX-2). The only person capable of perceiving SCP-XXXX-1 is SCP-XXXX-2, who describes the entity as a highly attractive female with whom he claims to be currently engaging in a romantic relationship.
Normally, the two are seemingly content to converse and interact in their containment cell, so they are quite safe. However, if anyone makes an attempt to flirt with or seduce SCP-XXXX-2 or does something that could be interpreted as such, the person will be assailed by SCP-XXXX-1, with the severity of the wounds depending upon how forward the victim was with their advances.
Obviously, I'm planning to add a backstory to this, but I'd love to hear what you think of the basic concept so far! If you'd like me to elaborate upon anything, feel free to let me know.
"Spartans never die, they just go MIA for years at a time and nobody questions it."