You can breathe air and water. Your aquatic heritage allows you to survive indefinitely beneath the waves while remaining perfectly comfortable on land.

Your internal anatomy is naturally grounded, a biological defense evolved to withstand the electrical discharges of deep-sea vents and the lightning-prone surface storms. You have resistance to lightning damage.

Your body lacks a rigid skeleton, consisting instead of dense, flexible muscle and cartilage. You can move through a space as narrow as 1 inch wide without squeezing. Additionally, your rubbery skin and shifting form make you difficult to pin down; you have advantage on ability checks made to escape a grapple.

Surrounding your mouth is a cluster of highly dexterous, sensitive tentacles. These appendages are capable of the same fine motor control as a humanoid hand, allowing you to manipulate your environment even when your primary limbs are occupied. You can use these tentacles to perform delicate tasks such as picking a lock, operating a small tool, or activating a magic item. While they lack the strength for heavy weaponry or shields, they are nimble enough to wield a weapon with the light property.

Evolution has gifted you with a pressurized reservoir of dark, alchemical ink. As a reaction when you take damage, you can release a cloud of blinding ink. Each creature within 5 feet of you must succeed on a Constitution saving throw (DC = 8 + your Constitution modifier + your proficiency bonus) or be Blinded until the end of its next turn. Once you use this trait, you can’t do so again until you finish a short or long rest.