Undead Sharkin (5e Race Variant)
From D&D Wiki
Sporting a shambling carcass, and unaging body, this sharkin variant strives to walk the earth forever. The base race is sharkin.
Age. You don't age anymore and can live forever or until killed by unorthodox means or by magic.
Size. Your size is comparable to a Sharkin subrace of your choosing.
Speed. Your base walking speed is 20 feet. You're swim speed is 40 feet.
Undead Fortitude. If you take damage that reduces you to 0 hit points, you must make a Constitution saving throw with a DC of 5 + the damage taken, unless the damage is radiant or from a critical hit. On a success, you drops to 1 hit point instead.
Vicious Bite. As a standard action, you may bite one target. You are proficient with vicious bite, which does 1d8 necrotic damage, 2d8 at 5th level, 3d8 at 10th level, and 4d8 at 20th level.