...Grace does have the potential energy to create impurities in Time, yes, but they seemed capable of creating the scars in the stream themselves. I'm not sure you could lure one, not unless it was starving already.

[ you need to take it back to the ten yard line, mister, this isn't a play that'll make it easy to score. ]

There's so many variables involved here, I'd fill this book and countless like it trying to list them all.