
llaletin |

Its going to depend on how the GM interprets Invisibility's wording; causing harm indirectly is not an attack and thus does not break the spell. As a GM, I would rule that casting Reverse Gravity wouldnt break Invisibilty, even if the caster ended RG when a foe was floating up in the air, as that would be no different to an invisible creature cutting the ropes on a rope bridge filled with foes (an example given in Invisibility's description).
Of course in casting RG, the caster will need to use verbal and somatic components, so a GM is within their right to say that the caster is only getting a +20 bonus to stealth vs the perception of foes, though said foes may soon find themselves distracted by other matters... :-)