The net result is that threats like Hazoret, Kalitas, [Card]Glorybringer[/Card], and just three-drops with high toughness in general, are surprisingly difficult to bring down and can easily take over the game against an opponent who showed too much respect for [Card]Bomat Courier[/Card]
Since Wizards went in development with the mindset of this being a joke set they could include mechanics that just dont work in Magic or are so completely out of left field that they make you do a double take
And the foiling works wonders for the art, especially the purple highlights around the central void
Some artifact payoffs, like Urza, Lord High Artificer and cards with affinity, might not care if the Opal taps for mana or not
Attacks alone in this case means that it is the only creature declared as an attacker if other creatures or token are then created and enter the battlefield attacking, Exalted still goes off, as they werent declared attackers