Wampus

Magic Constitution. The Wampus has Advantage on saving throws against spells and other magical effects, and its attacks count as magical.

Nondetection. The Wampus can’t be targeted or detected by any divination magic or perceived through magical scrying sensors.

Legendary Resistance (3/Day). If the Wampus fails a saving throw, it can choose to succeed instead.

Multiattack. The Wampus makes two Claw attacks and one Bite attack.

Bite. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 13 (1d20 + 3) piercing damage.

Claw. Melee Weapon Attack: +5 to hit, reach 10 ft., one target. Hit: 9 (1d12 + 3) slashing damage.

One with the Green. After any Wampus attack in any grassland or forest setting, and whether such attack is successful or not, the Wampus can use its Bonus action to meld and disappear into the ground cover, provided this ground cover is flora, without provoking an opportunity attack. When the Wampus does this, it immediately re-emerges up to 30 ft. away, in any available flora ground cover. When re-emerging, the Wampus is Invisible until it attacks, is hit for damage, or it chooses to end invisibility. 

Fae Rebuke. Any creature that damages the Wampus is momentarily surrounded by crackling light blue energy. That creature must make a DC 20 Dexterity saving throw, taking 28 (5d10 + 3) Lightning damage on a failed save or half as much damage on a successful one.

The Wampus can take 3 legendary actions, choosing from the options below. Only two legendary actions option can be used at a time and only at the end of another creature’s turn. The Wampus regains spent legendary actions at the start of its turn.

Disheartening Roar. All creatures within a 30 ft. radius of the Wampus and able to hear are hit with a ferocious roar from the Wampus. Any creatures caught in the roar must make a DC 18 Constitution saving throw or else become Disheartened until the end of the creature's next turn. The Wampus has advantage on any attack on a Disheartened creature, and, conversely, a Disheartened creature has disadvantage on any attack on the Wampus.

Rebuke All. All creatures within a 15 ft. radius of the Wampus are momentarily surrounded by crackling light blue energy. Any creatures caught in the blue energy must make a DC 20 Dexterity saving throw, taking 18 (3d10 + 3) Lightning damage on a failed save or half as much damage on a successful one. Any creature failing the save also suffers the Stunned status until the end of their next turn.

Flash Travel. The Wampus converts entirely to crackling light blue energy that condenses and disappears with a slight pop, only to reappear in another burst of blue energy up to 30 ft. from the starting point.