Contesting slot CB15 Asphyxiate. See also Card74934.

I can see this as a possible alternative, though it gives a creature destruction slot to off-color Discovery and is less of a straight removal card than Asphyxiate.

Well, Downfall is straight removal at common already - so I thought replacing one with -N/-N would add some variance (also this is a premier spot to actually use discovery as a dynamic threshold as opposed to the static "if your discovery is three or more").

I guess my reasoning for still wanting Asphyxiate is that it's in the realm of "relatively cost-effective removal", while Downfall isn't. I like downfall as a land destruction variant for black, but it's not an example of cost-effective creature destruction at 5 CMC. So to me there's a need for both cards. This card can sort of substitute for a cheaper creature removal, but that space being taken by an off-color Discovery card doesn't appeal to me. I figure black should be able to get a cost-effective creature removal option without having to use Discovery.

Well, this can be cost more efficiently. I just went into this thinking we should leave room for another straightforward removal spell at uncommon.

I definitely prefer this to Card74934.