Krazg, Scourge of the Mountain

This spell costs {1} less to cast for each zombie or dragon in your graveyard.
Flying, Trample, Menace
Whenever a Swamp enters the battlefield under your control, choose one —
•draw a card
• you gain 2 life
Whenever you lose life, this creature gains that many +1+1 counters until end of your next turn.
"We've killed their dragon! Nothing can stop us now! Wait... What's the corpse doing?"
-Beidux the Slayer, last words.