Half-Breed/Super-Munchkin question

[Olin Froid]

Originally Posted by Clipper

You can discard them normally without using any abilities at any time, including during combat. They would also qualify to power the Berserking bonus if you discard them for that instead. Note that your setup must remain legal, so if you are a Super Warrior-Cleric, you cannot discard the Super Munchkin without also discarding the Cleric card.

The only cards in play or in your hand that you can't discard with Berserking are the Warrior card you have in play and any card that says you can't discard it.

So let's say someone plays the card that gives +10 to monsters against my half-breed (the name escapes me, I remember it has a demon at a pulpit on it). Can I discard my half-breed card to power up the Berserking and then have the +10 be rendered useless against me? Or does it apply regardless of what I do after he plays it? And is that card copied if the monster is mated?