I will explain the case with Spark Double, but the procedure is the same with Felidar
Series: Gatecrash Item Type: Single Card Company: Wizards of the Coast Release Date: February 1, 2013 Brand: Magic The Gathering UPC: Stock #: 249010 Our Guarantees to You, Our Valued Customer
To do that youll need Aggravated AssaultAggravated Assault and something that makes you red mana on attacks
The sourcebook also covers the gods of Theros and its realms
While Dragons Rage Channeler is a great card in the current Modern environment, I have put her not that high up my list
A decade ago, From The Vault: Twenty was a Magic product with a similar goal, and while cards like Jace, The Mind Sculptor and Green Sun's Zenith feel deeply entrenched in the game, they were relatively new at the time