Needs to have an Attack type. And I suspect that in practice, it might as well read "+$2. Trash a Silver. If you do, each opponent gains a Copper or an Estate (their choice)". That's (a) weak (since it doesn't hurt as much as a Curse, and the vanilla +$2 just covers the lost Silver); (b) even worse than Sea Hag in terms of slowing down the game.
But maybe it would be good in combination with Trader, or something.