My favorite version of spider spawning is blue-green base with self mill. Hedron crab is the best card in the deck. The deck's only weakness was that it didn't interact well with what the opponent was trying to do, and it could lose to burn/tokens before it got going.
With the new lands from the expansion, I can easily add a white splash to my black splash. Rhox War Monk was the card I was really after, winning most aggro match-ups single handedly, and white actually offers some reliable removal to boot.
The idea is to play out all your creatures that cycle for other creatures, cycling your deck and filling your graveyard while pressuring durdlers and staving off aggro. Whenever you cast spider spawning you win, but it is very possible to win without it.
This deck has been performing insanely well for me over the past couple days. It's the highest casting card in the deck is 5 mana, so it curves out nicely almost every game. About half the cards in the deck cycle or draw, and it's packed with value from the graveyard and self mill. With spider spawning as the late game threat it has a more reliable finisher than most ramp or control style decks. Anyone who wants to give it a test or offer advice is welcome.
At the moment the only non-good match-up is against decks with talrand/guttersnipe plus negates.
Edit: The deck was still a bit slow, so I dropped the swamp for a plains and switched out a Soothsayer for a Baneslayer Angel. One less way to fill our graveyeard and draw what we need for more life gain and racing pressure. Should make the deck absolutely crush aggro and burn, and deal reliably with fliers. Makes Mentor a bit worse as well, but I was never really having trouble against slower decks anyway.
Edit 2: That done, the deck stalls to 8 mana extremely well every game. I might be able to afford a Craterhoof after all. Maybe I'll try it out in place of the quickling. Quickling was one of the cards making Mentor amazing, so I'll have to see if the damage to my draw engines is too high. The deck has been renamed to make the intentions of the variant plain without reading my theory.
Edit 3: This heavy into white already I can actually consider Brimaz or Banisher Priest, though those changes would make me a bit weak to board clears. Maybe Brimaz over a Masked Admirer or War Monk, and Banisher Priest over Reprisal? I could also consider a Rescue from the Underworld over a Treasured Find since I have better creatures to get back. What do people think?