Text (FS): Enchant creature with another Aura attached to it. ; Enchanted creature gets +3/+3 and has first strike, vigilance, and lifelink.
Having another aura on it is an enchanting condition, so the other aura goes away, this card can no longer legally enchant what it was enchanting and it goes to the graveyard. [D'Angelo 2007/05/15]
You can only put this card on a permanent that had an aura on it before it enter play. If it enters play at the same time as another aura, you cannot use that aura to enable this one. [Future Sight FAQ 2007/05/01]