David, Twisted Eugenicist

Wither, Haste.
{t}, Pay 2 life: Each opponent chooses a creature
they control, it gets a -1/-1 counter.
Sacrifice a creature: Search your library and or
graveyard for a spell of equal or lesser mana cost,
add that card to your hand.
Sacrifice a land: Search your library for any
creature and put it in your graveyard, you may cast
that spell anytime for its mana cost minus the total
amount of Wither counters on all players. (Does not
reduce colored mana.)