Ekans

You may cast Ekans from your graveyard if you
sacrifice a Bird, Egg, Frog, Mouse, or Rat in
addition to paying its mana cost to cast it.
Ekans can't have -1/-1 counters placed on it.
Whenever Ekans blocks, it gains first strike until
end of turn.
Whenever Ekans attacks or blocks, reveal the top
card of your library. If its a land, Ekans gains
infect until end of turn.(This creature deals
damage to creatures in the form of -1/-1 counters
and to players in the form of poison counters.)