As far as real world Physics is concerned, it is impossible for anything with mass to ever reach c (because among many other absurdities, it implies that the thing would end up with infinite total mass-energy, whatever that means). Even the fictional idea of transforming into light is problematic: in special relativity, any reference frame moving at c (light) will actually stop experiencing the duration of time. And as Algalon had already pointed out, the idea of light-speed information processing is also problematic since nervous systems are electro-chemical, in fact I don't think its possible for any biological system to information-process at c. Best not try making any real world sense out of it.