Monoblack

"The Black Problem" has two good, easy solutions-- the obvious one is Whirling Dervish, which no monoblack player can block, and can only be gotten rid of with Disks or Icys.

He was playing a monoblack weenie deck with 30+ creatures in it.

You can talk to him all day about how good high tide is in extended, or how good necropotence is in a monoblack deck, but he will still never play it.