As such, you can cast one side first, and later unlock the other side (the other door)
Nantuko Shade, Genesis, even Whipcorder was a decent dork
The one potential exception here is Pia Nalaar, which, while she does not technically have improvise, does provide a healthy set of stats and a relevant ability
The Ruinous Powers deck is Blue, Black and Red, and wants you to sacrifice your opponents for additional strength and play demons
The Dumb Cyclopean Titan is making fun of Cyclopean Giant, which is itself making fun of Cyclopean Tomb and Cyclopean Mummy
While 8 mana is certainly a lot, and that does preclude it from being in many Commander decks, basically any Green Commander deck should be playing Ugin, since its so easy to produce the mana in that color