More info
White
Uncommon
Casting Cost - 4W,
Non-Foil
Creature - Treefolk Warrior [3/5]
Defender At the beginning of combat on your turn, you may clash with an opponent. If you win, Sentry Oak gets +2/+0 and loses defender until end of turn. (Each clashing player reveals the top card of his or her library, then puts that card on the top or bottom. A player wins if his or her card had a higher converted mana cost.)
Illus. Warren Mahy