Crisis of Breath

Exhale softly and choose a medium or smaller creature that must breathe within range. The air within the creature’s lungs is violently expelled if they fail a Wisdom saving throw.
On the creature’s turn it may choose to gasp for air with its action. At the end of it's turn it must make a Constitution saving throw. If the save fails, the target falls unconscious and suffers disadvantage for all of its death saving throws for the duration of the spell.
If a creature used its action to breathe on its previous turn it makes its Constitution saving throw with advantage.

At Higher Levels: The size category of creature that may be affected by this spell increases by one for every spell level above 3rd.