Thunderheads

T: This creature deals 1 damage to any target. Whenever you cast an instant or sorcery spell, you may untap this creature.

Draw three cards, then put two cards from your hand on top of your library in any order.

Flying Whenever this creature deals combat damage to a creature, destroy that creature. Dredge 5 (If you would draw a card, you may mill five cards instead. If you do, return this card from your graveyard to your hand.)

(T: Add G.)

This creature enters with a +1/+1 counter on it for each creature card in your graveyard. 1, Remove a +1/+1 counter from this creature: Regenerate this creature. Dredge 6 (If you would draw a card, you may mill six cards instead. If you do, return this card from your graveyard to your hand.)

Boneyard Wurm's power and toughness are each equal to the number of creature cards in your graveyard.

1B: Return this card from your graveyard to the battlefield tapped.

(T: Add B.)