But doing both and giving this blue creature flash is just distasteful, to the point where I question why people would even want to play this in a Cube environment
Cascade lets you cast a spell then exile cards from your library until you exile a nonland card that costs less, which you can then cast for free
I bent my rules just a bit for this card, since it can keep my battlefield presence even in the face of a battlefield sweeper, and since the Spirit creature tokens have flying, they can continue the quest for coolness

Waters Angry Dog Deck 2002-06-21 YES 037 Wurm Token Alan Pollack Angry Dog Deck 2002-06-21 YES Atog Deck 2002 - Mini MTG Cards SET NUM CARDNAME ARTIST SOURCE DATE INFO 000 67/350 Counterspell Mark Romanoski Atog Deck 2002-06-21 000 132/350 Entomb Ron Spears Atog Deck 2002-06-21 000 57/350 Fact or Fiction Terese Nielsen Atog Deck 2002-06-21 000 128/143 Fire/Ice David Martin & Franz Vohwinkel Atog Deck 2002-06-21 000 60/143 Flametongue Kavu Pete Venters Atog Deck 2002-06-21 000 332/350 Island (Version 1) Scott Bailey Atog Deck 2002-06-21 000 333/350 Island (Version 2) Rob Alexander Atog Deck 2002-06-21 000 334/350 Island (Version 3) John Avon Atog Deck 2002-06-21 000 336/350 Island (Version 4) John Avon Atog Deck 2002-06-21 000 337/350 Island (Version 5) Terese Nielsen Atog Deck 2002-06-21 000 338/350 Island (Version 6) Darrell Riche Atog Deck 2002-06-21 000 335/350 Island (Version 7) Tony Szczudlo Atog Deck 2002-06-21 000 337/350 Island (Version 8) Larry Elmore Atog Deck 2002-06-21 000 338/350 Island (Version 9) Rob Alexander Atog Deck 2002-06-21 000 48/143 Nightscape Familiar Jeff Easley Atog Deck 2002-06-21 000 292/350 Psychatog Edward P

How much does Thunderwolf Cavalry cost
It's hard to know for sure, but you can try and put your thumb on the Planechase scale a little bit by thinking about when to roll in your turn