Magic Resistance. The pixie giant has advantage on saving throws against spells and other magical effects.

Grassy Camouflage. The pixie giant has advantage on Dexterity ( Stealth) checks made to hide in grassy terrain.

Innate Spellcasting. The Pixie Giant is an innate spellcaster. Its spellcasting ability is Charisma (spell save DC 5, +8 to hit with spell attacks). The Pixie Giant can innately cast the following spells, requiring no material components:
At will: Calm Emotions, Charm Person, Detect Magic

2/day each: Arcane Hand, Conjure Volley, Heal, Sunbeam

1/day each: Banishing Smite, Insect Plague, Tree Stride

Multiattack. The pixie giant can use one of it's auras. It then makes two attacks: one slam attack and one downward blow attack.

Slam. Melee Weapon Attack: +9 to hit, reach 5 ft., 1 target. Hit: 23 (6d6 + 2) bludgeoning damage. 

Downward Blow. Melee Weapon Attack: +9 to hit, reach 5 ft., 1 target. Hit: 32 (8d6 + 4) bludgeoning damage, the target must then make a DC 15 Strength Saving Throw, becoming knocked prone on a failed save. 

Faerie Aura. Each creature of the giant's choice that is within 30 ft of the pixie giant and aware of it must succeed on a DC 15 Wisdom Saving Throw or become charmed by the pixie giant for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the giant's Faerie Aura and Fiery Aura for the next 24 hours.

Fiery Aura. Each creature of the giant's choice that is within 30 ft of the pixie giant and aware of it must succeed on a DC 15 Wisdom Saving Throw or become frightened of the pixie giant for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to the giant's Faerie Aura and Fiery Aura for the next 24 hours.

The pixie giant can take 3 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 pixie giant regains spent legendary actions at the start of its turn.

Slam. Melee Weapon Attack: +10 to hit, reach 5 ft., 1 target. Hit: 23 (6d6 + 2) bludgeoning damage. 

Fey Step. The giant can magically teleport up to 30 feet to an unoccupied space it can see.

Fairy Dust (Costs 2 Actions). The giant rolls 5d8; the total is how many hit points of creatures this spell can affect. Creatures within 20 feet of the giant are affected in ascending order of their current hit points (ignoring unconscious creatures). Starting with the creature that has the lowest current hit points, each creature affected by this spell falls unconscious until the spell ends, the sleeper takes damage, or someone uses an action to shake or slap the sleeper awake. Subtract each creature’s hit points from the total before moving on to the creature with the next lowest hit points. A creature’s hit points must be equal to or less than the remaining total for that creature to be affected. Undead and creatures immune to being charmed aren’t affected by this spell.