Originally Posted by
Fatal
It still lose to shaman's activations, if opponent is way ahead if you can't finish it fast.
Actually i think
Novablast Wurm 3GGWW (7)
Creature — Wurm (7/7)
Whenever Novablast Wurm attacks, destroy all other creatures.
Is probably better in Elves mirror, if you get it ongoing you can't loose. It's quite slow which isn't good, but can answer any board state "IF" it attack.
Anyway, it's vs mirror only Elderscale is probably more universal vs some light removal decks, about Eldrazi I found they have big problems vs fast Progenitus (only answer is All is Dust which not always fast enough), but can be faster then Elderscale Wurm. Specially with chump blocks, vs Eldrazi I would rather recommend Novablast, single attack can clean table so even if they All in Dust before their lethal you get enough time to recover.