I had been kicking around an idea for a comic book series, sort of a cross between Batman and Silver Sable. The story was really going well, it had international intrigue and all sorts of neat stuff. Basically, if I was looking at comics and came across this, I'd totally buy it. I'd have to find someone else to draw it (it needs a superhero type artist, my stuff just won't cut this), but it was totally doable.
A scant time ago, I was talking online with another writer. I gave him a rough outline and description of the character.
He said, "You don't read superhero comics, right?"
I started getting a bad feeling. No, I don't. Why?
"You might want to read this." And he posted a link to the Wikipedia article on Marvel's Black Widow.
Aw, goddammit, not again!
There are a couple of differences -- my character didn't shoot energy bolts from her gauntlets, and there were no Spider-Man trappings to her. But there were enough similarities that I just about shit myself. And it was going so well!
I was trying to see if I could salvage it, make a few changes that would keep Marvel from crying foul, but I just see too many similarities to the characters. Even though it was accidental, no one will believe it.
So, that idea goes in the shredder. I hate it when that happens.