Shapechanger. The Heucuva can use a bonus action to polymorph into a Medium humanoid it has seen, or how it appeared in life. Its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

False Appearance (Polymorphed Form Only.) While Polymorphed the Heucuva's true form can be detected by non-visual senses such as touch or blindsight.

Turning Defiance. The Heucuva has advantage on saving throws against effects that Turn Undead. The Huecuva is considered CR 3 for the purposes of Destroy Undead.

Claw. Melee Weapon Attack: +4 to hit, reach 5 ft., 1 target. Hit: 5 (1d6+ 2) slashing damage plus 3 (1d6) poison damage. If the target is a creature, it must succeed on a DC 12 Constitution saving throw against disease or become poisoned until the disease is cured. Every 24 hours that elapse, the creature must repeat the saving throw, reducing its hit point maximum by 5 (1d10) on a failure. This reduction lasts until the disease is cured. The creature dies if the disease reduces its hit point maximum to 0.