Dread March

Create X 0/1 black Zombie Droid creature
tokens with march 2, where X is the number
of creatures and artifacts in your graveyard.
(Put two march counters on each of these creatures. During your upkeep, remove a march counter and put a +2/+0 counter on them. They have, "If this creature has no march counters on
it, it gains menace.)