You've got four abilities
So far weve seen the X count go up to 9 on Monument to Perfection, but most such creatures have toxic 1 or 2
Sure, this may not be as effective as Wakening Suns Avatar, but its still very fun
If you do, Thief of Existence gains "When this creature leaves the battlefield, target opponent draws a card." Creature - Eldrazi Yavimaya Granger Echo (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.) When this creature enters, you may search your library for a basic land card, put that card onto the battlefield tapped, then shuffle
The general idea here is to get a Goldspan Dragon into play, protect it with a Counterspell, and then untap the next turn and go off with infinite treasures