Badder Breath

As a Dragonborn, your breath weapon damage is normally a feature of your scale coloring (acid for black, poison for green, you know who you are) but something strange happened after you ate that weird-tasting fruit last night. You may now select the type of damage your breath weapon causes daily! If you're already familiar with spell selection, it's kind of like that, only whatever you ate means you have control over those sacs in your throat. The attributes of the breath weapon also adhere to the damage type, as follows:

Acid, Lightning, or Fire: 5 x 30 foot line; DEX save

Poison or Cold: 30 foot cone; CON save

Your resistance doesn't change, however. No, not even if you take the fruit and rub it all over your scales. I mean, go ahead, you be you, but you're going to be all sticky and it still won't change your natural resistance.