Primeval Companion

The Companion has a total number of d8 Hit Dice equal to your Barbarian level. It also gains all of the normal benefits of both short and long rests.

Once per long rest, when your Companion is reduced to 0 hit points, it can choose to instantly gain hit points equal to your Barbarian level instead of falling to 0.

When your Proficiency Bonus increases at 17th level, this Companion's bonus to its proficient skills and saving throws also increases by the same amount.

If your Companion moves at least 20 ft. in a straight line then hits a target with its Maul attack it deals bonus damage equal to your Exploit Die on hit.

Melee Weapon Attack: +4 + PB to hit, reach 5 ft., one target. Hit: 2d8 + 4 + PB, and a target equal to the Companion's size (or smaller) is knocked Prone.