Coastal Owlkeeper

Linger (Whenever you cast an instant or sorcery
spell, you may pay {2} and exile this card from
your graveyard to add the bracketed phrase to
that spell.)
[This spell can't be countered.]
When Coastal Owlkeeper enters the battlefield,
tap target creature with flying. That creature
can't untap for as long as you control Coastal
Owlkeeper.