Fterotós, Wings of Nyx

Constellation - Whenever Fterotos, Wings of Nyx
or another enchantment enters the battlefield
under your control, creatures you control gain
flying until end of turn.
{3}{u}{b}, Sacrifice an enchantment: Search target
player's library for an enchantment card and
put that card onto the battlefield under your
control. That player shuffles their library.