Flash (You may cast this spell any time you could cast an instant.)
Flying (This creature can't be blocked except by creatures with flying or reach.)
Whenever Salvation Swan or another Bird you control enters, exile up to one target creature you control without
flying (This creature can't be blocked except by creatures with flying or reach.). Return it to the battlefield under its owner's control with a
flying (This creature can't be blocked except by creatures with flying or reach.) counter on it at the beginning of the next end step.