Asher's Zombie

Undead Fortitude. If damage reduces the zombie to 0 hit points, it falls prone and becomes incapacitated. After 1 minute the zombie rises with 2d6 hit points removing the prone and incapacitated conditions, then regenerates 1d4 hit points per minute until it reaches its maximum. If the zombie suffers damage during the initial minute, it is destroyed and both it and the amulet used to summon it crumble to dust.  

Attacker. The sidekick gains a +2 bonus to all attack rolls.

Improved Critical. The sidekick’s attack rolls score a critical hit on a roll of 19 or 20 on the d20.

Multiattack. The zombie can make two slam attacks.

Slam. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 3) bludgeoning damage.

Second Wind. The sidekick can use a bonus action on its turn to regain hit points equal to 1d10 + its level in this class. Once it uses this feature, it must finish a short or long rest before it can use it again.