Eradicator, Spark Horn Dragon

(This ability is active if you have four or more damage):When this unit attacks a vanguard, this unit gets +5000 until end of that battle. : 1-card with "Eradicator" in its card name] When this unit's attack hits a vanguard, you may pay the cost. If you do, your opponent chooses one of his or her rear-guards, and retires it.