Goblins vs Zombies: Black Dragon Card

In the base game you have 3 Guardians of three different colors (Red, Blue, and Green), each with the same ability. The Black Dragon is a new Guardian with a different ability, so now you will have 4 Guardians. At the beginning of the game each Player chooses one Guardian, or takes one at random. The Card text reads: When a Zombie in your field ENTERS: Destroy that Zombie. Then choose an Area in your Field, destroy up to 4 Zombies on that Area (Cannot destroy [b](B)[/b]). Then FLIP this card.