Maw slaughter. Each time the Z-Rex damages an organic creature with its bite attack, its bite gains +1 bonus (cumulative) to its necrotic damage. This bonus resets after 1 hour, at which point the festering blood of his victims spills from his teeth.

stench. Any creature that begins its turn desire within 10 feet of the Z-Rex must succeed on a DC 16 constitution saving throw or it will be poisoned until the beginning of its next turn. On a successful saving throw, the creature is immune to the stench of the Z-Rex for 24 hours.

Dead fortress. if the damage reduces the Z-Rex to 0 hit points, it must make a constitution saving throw with DC 5 + damage taken, unless the damage is radiant or from a critical hit. If successful, the Z-Rex is reduced to 1 hit point.

multi-attack. the Z-Rex performs two attacks: one with its bite and one with its punch. they cannot both attacks against the same target.

bite. Melee Weapon Attack: +10 to hit, reach 10ft, one target. hit: 20 (2d12 + 7) spring damage plus 13 (2d12) necrotic damage. if the target is a creature, it must form a dc 16 throne of salvation or it will become infected. and infected creatures take a +1 penalty to all rolls they make. they can redo their saving throw at the end of each of their turns. Each time a creature fails to make this save, the penalty to its die roll increases by 1.

Knock. Melee Weapon Attack: +10 to hit, hit 10 feet, one target, hit 20 (3d8 + 7) bludgeoning, damage. if the target is a creature, it must make a DC 17 energy saving roll or be face-down with the ether or be pushed back 10 feet. The Z-Rex may choose to perform this reckless attack, giving it the upper hand. If he does, the next attack against him also has an advantage.