Restrain Dragon

:[ 1 & Put this unit into your soul] When a locked card is unlocked, you may pay the cost. If you do, lock that unlocked card. (The locked card is turned face down, and cannot do anything. It is unlocked and turns face up at end of the owner's turn) /(Active if you have one or more face up G units in total on your or G zone):When this unit attacks a vanguard, this unit gets +4000 until end of that battle.