Satyr Of The Plague

({p/b} may be paid with {b} or two life)
Whenever Satyr Of The Plague deals combat damage to a player, you may gain control of a creature that player controls with converted mana cost X or less. It becomes a black rogue in addition to its other colors and types and gains "At the beginning of your upkeep, put a -1/-1 counter on this creature." (It goes in its owner's graveyard when it dies.)