Hmm. There is precedent for this effect: Magewright's Stone. This is obviously a lot more expensive, but it's a) repeatable and b) doesn't take up a deck slot. So I guess the cost seems about right (although perhaps or would be more natural than ).

Truth was I didn't know what to do for the ub land in the cycle.

Heh. Fair enough then.

All creatures get -2/-0? Good old Marsh Gas. If you can smell it, it's too late.