Baca's Exuberant Charm

The castor chooses a target in range, they make a Wisdom saving throw. If they succeed, they make additional saves at the end of each of your turns. The creature becomes charmed,  this affect lasts until they fail or the spell ends. For each time after the first that the target makes the save, the DC increases by +1, to a maximum of 25. If or when they fail, they become charmed and are no longer hostile to the castor if they were. The spell and charm effect ends 1 hour after the casting of the spell. 

At Higher Levels. If cast at at 9th level, the DC increases by +2 per round, and the maximum DC increases to 28.