Sunavalon Bloom

When this card is activated: If you control a Link-4 or higher Plant monster when this effect resolves, negate the effects of all face-up monsters your opponent currently controls. During damage calculation, if your Plant Link Monster battles: You can activate this effect; it gains ATK equal to the combined ATK of monsters it currently points to, until the end of this turn. (These effects remain even if this card leaves the field.) You can only use this effect of "Sunavalon Bloom" once per turn. You can only activate 1 "Sunavalon Bloom" per turn.