One creature of your choice that you can see within range feels an invisible grasp around its throat and it starts suffocating it. The creature must make a Constitution saving throw. On a failure, it takes 2d6 force damage and is forced to hold its breath for the duration of the spell. On a successful save, it takes half as much damage and doesn't hold its breath.
An affected creature cannot speak or cast spells, and at the start of each of its turns it takes an additional 2d6 force damage. At the end of each of its turns, an affected creature can make another Constitution saving throw, ending the effect on itself on a successful save. If an affected creature fails their Constitution saving throw three times, they are incapacitated for 1d4 rounds.
At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, you can choose an additional creature for each slot level above 3rd.