Cosmic Griffin

Keen Sight. The griffon has advantage on Wisdom (Perception) checks that rely on sight.

Star Light.The griffon was advantage on Dexterity[skill]Stealth checks at night.

Dive. If the griffon moves more than 30ft straight down while flying towards a creature the target must succeed on an DC 22 strength or be knocked prone. Once prone the griffon can make one beak attack.

Legendary Resistance (2/Day). If the griffon fails a saving throw, it can choose to succeed instead.

Multiattack. The griffon makes two attacks: one with its beak and one with its claws.

Beak. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 8 (1d8 + 4) piercing damage.

Claws. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage.

Starie Night. Spell attack: [rollable]+4 Once per turn the creature beats its star filled wings and cast the Hypnotic Pattern spell.

Sneak Attack. When the griffon is flying at night is seamlessly blends into the night sky that it is granted sneak attack dealing 10d6.

The griffon can take 4 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The griffon regains spent legendary actions at the start of its turn. 

Smash and Grab (Costs 3 Actions). When the griffon is 40 feet off the ground it can dive bomb a medium size creature or smaller and attempt to pick them up with a DC 22 strength save, on a fail the creature is picked up and flown 40 feet up before the creature is dropped.

Blend (Costs 1 action). While in the sky the Griffon can hide it's self gaining sneak attack on it's next turn.