You have advantage against saving throws against being frightened, wisdom (perception) checks, dexterity (stealth) checks made to hide in dark or dim lighting, and on melee attacks against anyone who doesn't have all their hit points.

You have disadvantage against checks that rely on eyesight in daylight, as well as attack rolls.

If the chupacabra is flying and dives at least 30 feet straight toward a target and hits it with a melee weapon attack, the attack deals an extra 7 (2d6) damage and the target must make a DC 15 Strength saving throw or be knocked prone.

Any creature other than a chupacabra that starts its turn within 5 feet of the chupacabra must succeed on a DC 12 Constitution saving throw or be poisoned until the start of the creature's next turn. On a successful saving throw, the creature is immune to the stench of all chupacabras for 1 hour.

The chupacabra's long jump is up to 20 feet and its high jump is up to 10 feet, with or without a running start.

The chupacabra can take the Disengage or Hide action as a bonus action on each of its turns

Melee Weapon Attack:  Reach 5 ft., one target. Hit: 2d6 + Prof Bonus piercing damage and the chupacabra. If the target is a creature, it must succeed a DC 15 Constitution saving throw. On a failed save, the target becomes poisoned. On Successful save the target is safe from being poisoned and takes the damage normally.

+7 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage. Instead of dealing damage, the chupacabra can grapple the target (escape DC 15).