Neiui and Ardorá

Flying, Menace
Two-personed {1}{u}: The first time Neiui and Ardora exit the battlefield, exile them unless you pay {1}{u}. If you do pay this, return it to the battlefield tapped.
Neiui and Ardoras' power and toughness are equal to the number of creatures you control with flying, menace, vigilance, haste, changeling, and double-strike plus 1.