Ponman

When Ponman enters, if {w} was spent to cast it, put a vigilance counter on it and you gain one life.
When Ponman enters, if {b} was spent to cast it, put a deathtouch counter on it and each opponent loses one life.
When Ponman enters, if both {w} and {b} was spent to cast it, put a lifelink counter on it and draw a card.

A simple organism that takes life one square at at a time.