Hold Breath. While out of water, the octopus can hold its breath for 30 minutes.

Underwater Camouflage. The octopus has advantage on Dexterity (Stealth) checks made while underwater.

Amphibious. The frog can breathe air and water 

Shadow Stealth. While in dim light or darkness, the shadow octopus (Familiar)  can take the Hide action as a bonus action.

Living Shadow. While in dim light or darkness, the shadow octopus (Familiar) has resistance to damage that isn’t force, psychic, or radiant.

Superior Dark vision. Your familiar's dark vision has a radius of 120 feet. 

Limited Telepathy. Your familiar can magically communicate simple ideas, emotions, and images telepathically with any creature within 100 ft. of it that can understand a language.

Shape changer. Choose two CR 0 beasts. Your familiar can use its action to Polymorph into one of these beasts, or back into its true form. Its statistics are the same in each form, except for changes to speed. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Tentacles. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 1 (1d1) bludgeoning damage. The target is grappled (escape dc 10) Until this grapple ends, the octopus can't use its tentacles on another target

Ink Cloud (Recharges after a Short or Long Rest). A 5-foot-radius cloud of ink extends all around the octopus if it is underwater. The area is heavily obscured for 1 minute, although a significant current can disperse the ink. After releasing the ink, the octopus can use the Dash action as a bonus action.

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