I like the idea of a card that can be driven by two different elements independently. I like what you did with the card and how it fits the name too.
As for how to target one creature and then another we wold be asking Zanz to do a big rewrite of the code unless there is some shortcut in making it work. But I think this is an idea that has come up time and again so maybe it will happen eventually.
The unupgraded and upgraded cards are quite different despite their similar appearances.
The unupped one is much more powerful than the upped one unfortunately.
If I play upped on my photon and enemy Ruby Dragon, I get a 7 attack creature and the dragon becomes about the same. That is great I can get so much attack. But it doesn't totally ruin the Ruby either.
On the other hand, If I play the unupped in the same situation, I get a 3|3 photon and the enemy gets a 3|3 ruby dragon. That seems way more powerful than the upped version as it kills high attackers and lets not act like high attackers are not the favorite card of the game.
That said I think the cards are relatively well balanced as stand alones. The effects are so different for the upgraded and unupgraded I would just like to see them reconciled a bit.
Some obvious question/ possibilities.
If I have an antimattered Archangel, -7 attack, and I use the upped version on an enemy archangel, then both get 0 attack right? If so this would be a great counter to antimatter for a good price.
The other question is chimera. The unupped version would be an incredibly hard counter to chimera (mutation already is I suppose).