Embrace of the Waves

Choose a humanoid within range, the humanoid is forced to make a saving throw, upon failure he is surrounded by illusory waves and sea foam, copmletely beffudling his mind, he can only stand in that location, every turn repeat the save, the DC lowers by one for every turn spent inside the illusion

Using a Higher-Level Spell Slot. You can target one additional Humanoid for each spell slot level above 2.