Quackthulhu

 is a gigantic mutated duck created by Matthew Mercer.

Appearance
Quackthulhu is a massive, swollen duck-like creature of ill green feathers and flesh, burning red eyes, and four terrible whipping tentacles protruding from its body. A glowing stone that fell as a shooting star is embedded within its back, with dark veins writhing around where it pierces its body.

Quackthulu was an ordinary duck until a meteor crashed into its duck pond, implanting itself into his back, and mutating it into a gigantic aberration. The Darrington Brigade killed it after a long, hard-fought battle, removing the meteor to take back to Doolan Tversky for a 10,000 gp reward.

Abilities
Matt published Quackthulhu's stat block on Twitter. The following abilities were demonstrated in.


 * Legendary resistances (3x per day)
 * Damage resistances: bludgeoning, piercing, and slashing from non-magical weapons
 * Damage immunities: necrotic
 * Multiattack: each tentacle can attack and attempt a grapple each turn
 * Soul-Wrenching Quack: paralyzes opponents failing a DC 16 wisdom saving throw
 * Legendary Actions (3x per round):
 * Ground Slam - opponents failing a DC 14 strength saving throw are pushed 10 feet away
 * Tentacle attack
 * Ability to charm/take control of Lionel, possibly through his duck totem connection