Altar of the Void

When Altar of the Void enters the battlefield,
lose 3 life and exile the top 3 cards of your
library. You may play cards exiled with Altar of
the Void.
Whenever you play a card from exile,
you gain a Madness counter. At the beginning of
your upkeep, exile X cards from the top of your
library where X is equal to the number of
Madness counters you have.
At the end of your turn, if you have 7 Madness counters, transform Altar of the Void