Corrupted Kobold

Sunlight Sensitivity. While in sunlight, the kobold has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.

Berserk. Whenever the corrupted kobold starts its turn with 40 hit points or fewer, roll a d6. On a 6, the kobold goes berserk. On each of its turns while berserk, the kobold attacks the nearest creature it can see. If no creature is near enough to move to and attack, the kobold attacks an object, with preference for an object smaller than itself. Once the kobold goes berserk, it continues to do so until it is dies or regains all its hit points.

Multiattack. The kobold makes two attacks.

Boneclub. Melee Weapon Attack: +6 to hit, reach 10 ft, one target. Hit:  8(1d8 + 4) bludgeoning damage.

Sweeping club. Melee Weapon Attack: +6 to hit, 10ft cone in front of creature, hits all creatures within range. Hit:  8(1d8 + 4) bludgeoning damage.

Slam. Melee Weapon Attack: +8 to hit, reach 5 ft., one target. Hit: 16 (2d10 + 5) bludgeoning damage. If the target is a creature, it must succeed on a DC 15 Constitution saving throw or have its hit point maximum reduced by an amount equal to the damage taken. The target dies if this attack reduces its hit point maximum to 0. The reduction lasts until removed by the greater restoration spell or other magic.

Pool of Corruption. Ranged spell attack. The corrupted kobold vomits a pool of corruption in a 10ft circle with 15 ft of it. Any creature caught in this must make a Dex save to avoid it. They take 2d8 poison damage. Half damage on a save. Additionally, if they failed, they must then make a Con save every 1d4 rounds to resist the affects. On a fail, they take a further 2d8 poison damage. On a success they remove the corruption from their bodies.