Blastortle

You've tinkered with your very nature, building a cannon into your shell, gaining the following benefits:

• Increase your Strength/Constitution/Wisdom score by 1 to a max of 20.
• You get proficient with Tinker's tools.
• You get a bonus action which you can only use while benefiting from Shell Defense. As a bonus action, you can activate your cannon from the inside, blasting your choice of water (magical bludgeoning) or energy (force damage) in a 30ft cone. Each creature in the cone makes a DC (8 + your proficiency bonus + the ability you increase with this feat) Dexterity save. On a failure, a creature takes damage of the type you choose. The damage is 2d6 x your proficiency bonus or half damage on a success. Once used, you can't do so until you finish a short or long rest.