booster boxes of pokemon cards Mega Evolutions Perfect Order Bundle plus 9 of the OG Pokes including Mew ex and Alakazam ex Pokemon Mega Evolution Chaos Rising

This lets you hold up mana, react to your opponents plays, and deploy threats at instant speed

Suspect Everyone's guilty until proven innocent

However, take this all with a grain of salt until an official announcement is given

This can be done anytime you have priority, even after blockers are declared, so if they block your mysterious 2/2 with a 3/3, but you turn it face up so that your attacker becomes a 6/6, your creature will defeat the 3/3 no problem

Given the many changes the card game has undergone since its release, players both new and returning may need a refresher of the rules

I see only 3 moments you want to activate the effect