Arcanovirus Zombie

Necrotic Absorption. Whenever the zombie is subjected to necrotic damage, it takes no damage and instead regains a number of hit points equal to the necrotic damage dealt.

Regeneration. The zombie regains 10 hit points at the start of its turn if it has at least 1 hit point. If the zombie takes radiant damage, this trait doesn't function at the start of the zombie’s next turn.

Undead Fortitude. If damage reduces the zombie to 0 hit points, it 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, the zombie drops to 1 hit point instead.

Multiattack. The zombie makes two slam attacks and then makes one bite attack, all against the same target.

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

Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 4 (1d6 + 1) piercing damage and the target must succeed on a DC 13 Constitution Saving throw or be infected with Arcanovirus. Creatures immune to the poisoned condition have advantage on this saving throw.

When a creature is infected with Arcanovirus, its aging process quickly accelerates and it ages a full decade every 24 hours, until the disease is removed. After in a number of hours equal to 1d12 + the creature's Constitution score, the creature loses immunity to the poisoned condition it it previously had it, becomes poisoned for the rest of the duration and loses the ability to cast spells if it previously could. This poison cannot be removed until the disease is cured. After the creature dies of old age, it rises as an Arcanovirus Zombie in 7 (4d4 - 3) days.