Hey there. Thinking of writing a roleplay with an alternate universe Spider-man theme. I'm not sure if this will be a popular theme here, but I figure it would be worth a shot.
Perhaps, Peter Parker (aka Spiderman) gets into a serious relationship with Gwen Stacy, which leaves Mary-Jane Watson slightly jealous. Somehow, the black venom symbiote finds its way to M.J. and begins to twist her feelings into an uncontrollable downward spiral. She may kidnap Gwen, take her feelings out on Spiderman, or make some other kind of attempt to drive the two apart. Maybe Mary Jane is the girlfriend and Gwen is the psychotic crush with super-powers; it could work in either scenario. Gwen could even seek revenge on Spiderman for the death of her father, then becomes twisted from her emotions for Peter Parker.
I'm even open to having other canon characters used. If you have an idea, sling it forward and we'll work something out. Input is definitely open and encouraged. If you don't have a solid knowledge of Marvel and Spiderman comics, and you're still interested, we can figure something out.