Cosmic Hero, Grandsub

(This ability is active if you have one or more face up G units in total on your or G zone):When this unit's is increased due to an effect from one of your cards, if this unit's is 13000 or greater, choose one of your vanguards, until end of turn, it gets +4000, and "VC:When this unit's attack hits a vanguard, your opponent chooses one of his or her rear-guards, and retires it.". (It does not activate from increases due to boosting or guarding)