Increase one ability score by 2 and another by 1 or three ability scores by 1

Your size is medium 

You have a walking speed of 30ft and a swim speed equal to your walking speed

You are Humanoid

Accustomed to life in trenches and deepwater areas, you have superior vision in dark and dim conditions. You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can’t discern color in darkness, only shades of gray.

You can breathe both air and water.

You have advantage on Dexterity (Stealth) checks made while underwater.

In addition to your humanoid arms, you have eight tentacles which replace your legs.

• You have two “minor arm” tentacles. These tentacles can be used to lift a number of pounds equal to five times your Strength score. You can use these to do the following simple tasks: lift, drop, hold, push, or pull an object or a creature; open or close a door or a container; grapple someone, or make an unarmed strike. Your DM might allow other simple tasks to be added to that list of options. They can't wield weapons or shields or do anything that requires manual precision, such as using tools or magic items or performing the somatic components of a spell. You can only have a single creature grappled by your tentacles at any given time

• You have six “leg” tentacles. These tentacles help you walk, swim, and do anything else that a humanoid can do with its legs. However, the extra four “legs” give you advantage on Strength throws against being knocked prone.