Multiattack. The thri-kreen makes two Gythka attacks or four Psychic Bolt attacks.

Gythka. Melee Weapon Attack: +4 to hit, reach 5 ft., one target. Hit: 10 (2d8 + 1) slashing damage.

Psychic Bolt. Ranged Spell Attack: +6 to hit, range 60 ft., one creature. Hit: 6 (1d6 + 3) psychic damage.

Drain Vitality (Recharges after a Short or Long Rest). The thri-kreen targets one creature it can see within 30 feet of itself. The target must make a DC 14 Constitution saving throw, taking 32 (5d12) necrotic damage on a failed save, or half as much damage on a successful one. The thri-kreen regains hit points equal to the damage dealt.

Chameleon Carapace. The thri-kreen changes the color of its carapace to match the color and texture of its surroundings, gaining advantage on Dexterity (Stealth) checks it makes to hide in those surroundings.