This plus Mothdust Changeling = How many creature types are there now? 430? Hope you've got an Obstinate Familiar. Or add Hive Mind for the instant win.

There are 223 creature types now. Still, the fact that they've gone with design space allowing creatures of every type at once means they're never going to be able to use space like this, simply because the 223 number isn't something players need to be forced to keep track of constantly just to figure out what the game state is supposed to be.

Although, ironically, a 3-card combo, especially a 6+ casting cost combo, is hard enough that probably is ok, not that they'd actually print this. Which means you're restricted to Battle Of Wits decks, and creatures with legimately many subtypes :)

Thought about it, and assumed it was okay. If you cast this with a changeling on the table, you'll probably lose, since, as soon as you draw a card and you don't have one, you lose the game. So, yeah, if you have that large a library, and you were able to cast a spell with a converted mana cost of 7, go nuts and draw 223 cards.

My biggest problem I have with this card is your opponent's ability to make you lose spontaneously with a card like Blades of Velis Vel. It wouldn't happen in my block, though, and it would be such a rare situation in real life, that it would be kind of funny. I don't like come out of nowhere blowouts, but a card like this having such a strange answer is kind of cool.