Ok so me and a friend where discussing this but can Mew use Regidrago VStar's Apex Dragon as it's move?
Genome Hacking: Choose 1 of your opponent's Active Pokémon's attacks and use it as this attack.
Regidrago VStar's attack
Apex Dragon: Choose an attack from a Dragon Pokémon in your discard pile and use it as this attack.
I feel it should not work unless my opponent has a Dragon Pokémon in there discard pile. But my friend has been using my own discard pile.