Death Dog

The death dog makes two Bite attacks.

Melee Weapon Attack: +4 to hit, reach 5 ft.. Hit: 4 (1d4 + 2) piercing damage. If the target is a creature, it is subjected to the following effect.
Constitution Saving Throw: DC 12.
First Failure: The target has the Poisoned condition. While Poisoned, the target's Hit Point maximum doesn't return to normal when finishing a Long Rest, and it repeats the save every 24 hours that elapse, ending the effect on itself on a success.
Subsequent Failures: The Poisoned target's Hit Point maximum decreases by 5 (1d10).