Decree of Silence

combo with power conduit and sculpting steel you can have a eleven counter spell buffer zone plus take of four per turn. CAN ANYONE SAY GOD LOCK!

I put this in EDH a lot. If you can get combo elements running with it such as Hex Parasite, Power Conduit or Clockspinning this becomes a nifty little lock. Also useful as a nigh uncounterable counterspell + cantrip in a pinch. Decree of Annihilation is my favorite one though

This has some keen and extremely powerful abilities, but is expensive. First, it counters when you cycle it, so the counter is as a card ability, so the decree cant be countered itself except with a stifle, etc.... Second you can combo this for a pretty damn hard lock, although not quite an Arcane Lab or Stasis style lock. My fav is two Forgotten Ancients and a Spinal Parasite. Every spell the play, even if it's countered, gives you two +1/+1 counters, which can be moved to the Spinal Parasite to remove depletion counters at sacrifice speed. So each spell they play gives you the tools to counter it.

Extremely expensive, but extremely powerful if use correctly. Must be comboed with clockspinning to remove the counters from it though.