Pitch-black Dragon

Dark Matter (When you cast this creature, place a
time counter on X number of lands you control, where
X is this creature's converted mana cost. If a land
with a time counter would untap, its controller removes
a time counter from it instead.)
Flying
Whenever Pitch-black Dragon attacks, you may
put a time counter on a land you control and tap
it. If you do, each opponent sacrifices a
permanent.