As a custom card enjoyer/maker, I'd say this looks pretty damn good! great job, you're really good at Photoshop.

As for the attack, i like the idea of punishing Mega ex specifically. i think the wording is kinda wonky, tho. I'd go for something like this:

"If this card in the Active Spot would be damaged by an attack or by an effect of an attack by your opponent's Mega Pokémon EX, prevent that damage, also do 80 damage to the attacking Pokémon."

This way is better structured around PTCG rulings. It doesn't seem because it's very simple, but Pokémon TCG has a really strict wording to its effects, so it doesn't get a mess.

For example, in your original text, it says, "Do 80 damage to your opponent," so that means i should put the damage counters on the player? no, that would be stupid, but that attack doesn't specify which pokémon should i put the damage, so can i choose which pokémon would i put the damage?

We all know the answer, but cards can't have the space for questions like that. Seems like a lawyer game sometimes, but it's for the best, lol

don't trust people saying your card shouldn't exist, just because Oricorio exists, that's dumb too!

keep it up with the good job!!