Choose One--Each player puts the top seven cards of their library into their graveyard; Or, creatures get -5/-0 until end of turn; Or, choose a card you own from outside the game with a converted mana cost of two, and put it in your hand. Exile Forbidden Charm.
For Challenge # 106. My initial reaction was to give this charm some sort of twist. But I realized that Hybrid charms were already a twist and I should learn to settle down. So I just chose the guild with the least overlap, and called that my bonus challenge.
Mill is easy. I'm uncomfortable with black milling opponents (I know it can... I just think it's odd), but milling everyone feels black, so I stuck that. -5/-0 to everyone is obviously blue, but it's also a callback to Marsh Gas. Once again, it doesn't quite feel black, until it's happening to everyone.
Third, wishing feels black thanks to tutoring, and wishing for something specific feels blue, thanks to blue tutoring. Originally, I wanted to get a card that cost 3 to make this card feel like it had Transmute for the sideboard... but I'm pretty sure that would be broken. Besides, I get the impression that this would make a more interesting round 5 play, and I love the idea of forcing a player to chunk up their sideboard full of 2 cost cards.