Mephitic Croak 2014

You release an intensely loud burp of acidic gas in a 15-foot cone. Creatures in the area take 2d6 acid damage plus 2d6 thunder damage, or half as much damage with a successful Dexterity saving throw. A creature whose Dexterity saving throw fails must also make a successful Constitution saving throw or be stunned and poisoned until the start of your next turn.

When you cast this spell using a spell slot of 3rd level or higher, both acid and thunder damage increase by 1d6 for each slot level above 2nd.