Faeria

Couple of notes on this one:

A)The Illusion gets buffed by the attack/life of the creature, not just +1/+1, so playing 0/2 creatures will mess up your ratio. Bloated Toad will give you a full +3/+3.
B)It looks like playing in practice mode won't pop this. I had to do it on a wild mission, although you need not win the mission.
C)It won't pop until the end of the game, so don't fear when you play it and it doesn't pop immediately.

I'm not 100% sure if you have to hit 20/20 on the nose or if you can overshoot, I hit it on the nose as I only played 1/1's, 2/2's, and 3/3's. I padded my deck with storytellers and husks to draw the nerds quickly to play.

Basic decklist:
3 x Farm Boy
3 x Balloon Fish
3 x Storyteller
3 x Ruby Fish
3 x Bloated Toad
1 x Illusion of Grandeur
3 x Barrensky Vermin
1 x Doomgate, Door to Obilvion
2 x Flash Salmon
3 x Haunted Husk
2 x Shaytan Assassin (to help control the board)
3 x Rakoan Illusionist