Amass 4, mill four, deal 4, gain 4
a1a-32-mew-ex is as strong as opponent's Active Pokemon, copying its attack with Genome Hacking and attacking your opponent's Pokemon with it
A build probably exists that has a mill plan meshed together with a ramp into Ulamog, the Ceaseless Hunger plan
Still, if you had 3 creatures that you flickered even twice, that's 6 life your opponent is losing just from the call ETB, and could turn certain cards that make creature tokens even scarier
The card I'm talking about is the following: Thunder King Rai-Oh is one of the best cards the GX manga gave us and has been a staple in many decks ever since (safe the March 12 format, but lets forget about that horrible period)
1 2 "4Kids Entertainment Signs New Five-Year Agreement With Pokmon USA" (PDF) (Press release)