Baskling

Amphibious. The baskling can breathe air and water. 

Keen Smell. The baskling has Advantage on Wisdom (Perception) checks that rely on smell.

Necrotic Bleaching. When the baskling takes 10 or more Necrotic damage in a single instance, it gains Disadvantage on the next attack roll it makes before the end of its next turn.

Bloodlust. When the baskling makes a melee attack against a creature that has blood and doesn't have all of its Hit Points, it can gain Advantage on the
attack roll. The baskling can use this trait a number of times equal to its tamer's Proficiency Bonus, and regains all expended uses when its tamer finishes a Long Rest.

Palytoxin 1. The first time on each turn that the baskling hits a creature with its Bite attack, the target takes an extra 3 (1d6) Poison damage. This improvement doesn't function if the baskling's Necrotic Bleaching trait triggered since its last turn.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft. Hit: 4 (1d8+2) Piercing damage.