Azbernok, Writhing Terror

Trample
When you draw a card, you lose X life where X is the cards mana cost. If you cast a spell, you gain X life where X is twice to how much that spell's mana cost.
Avoid the tree with a crocodile grin and sharp branch-like claws, for he will deal those who are deserving of answers, the messages of death and corrosion.- Tale of the Mythical Trees