Uncountable infinities in Magic

[jack]

Update, someone else raised a very similar question on a message board. Indeed, using much the same technique I suggested, and I had found that link once before, but forgotten about it.

Page 1
Page 2

On page 1, someone asks a rules question that's a particularly apposite example of uncountable rules:

* The defender has generated an infinite number of small blocking creatures
* (Using a combo which involves mana burning down to a negative infinite amount of life!)
* The attacker has a spell which will win the game if any creature is unblocked
* The attacker uses two Nacatl War Pride, which when it attacks copies itself for each defending creature
* And turns both Nacatl War Pride into creatures that also are doubling season ("whenever a counter is put into play, instead put twice that many into play", although I think only the first one is relevant). Thus the second one puts an infinite number of creatures into play, to which an infinite number of doubling effects apply
* And asks "Will there be any unblocked attacking creatures?"

It's a particularly good example, because the cardinality is exactly relevant: the defender is exactly trying to make a bijection between blocking creatures and attacking creatures, and the attacker wants to know if there will always be an excess attacking creature.

On the second page someone proposes an explicit bijection (or rather, absence of a bijection).
I think this is functionally equivalent to my example.