Test Chamber

When you cast this spell, mana cannot be spent
to cast it.
Target opponent mills 4 cards. If a noncreature
card is milled this way, you may draw a card. If
a land is milled, proliferate. (You choose any
number of permanents and/or players with counters
on them, then give each another counter of a kind
already there).
"Knowledge is not instantaneous."