Innate Spellcasting (Yuan-Ti Form Only). The yuan-ti's innate spellcasting ability is Charisma (spell save DC 14). The yuan-ti can innately cast the following spells, without providing material components:

At will: animal friendship (snakes only)

3/day: suggestion

Magic Resistance. The yuan-ti has advantage on saving throws against spells and other magical effects.

Shapechanger. The yuan-ti can use its action to polymorph into a Medium snake, or back into its true form. Its statistics are the same in each form. Any equipment it is wearing or carrying isn't transformed. It doesn't change form if it dies.

Spellcasting. The yuan-ti is a 6th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 14). It has the following sorcerer spells prepared:

Cantrips (at will): mage hand, minor illusion, poison spray,true strike

1st level (4 slots): absorb elements, detect magic, shield

2nd level (3 slots): mind spike, see invisibility

3rd level (3 slots): counterspell, dispel magic

Sorcery Points. The yuan-ti has 6 sorcery points. It can spend 1 or more sorcery points to gain one of the following benefits:

 Quickened Spell: When the yuan-ti casts a spell that has a casting time of 1 action, the yuan-ti can spend 2 sorcery points to change the casting time to 1 bonus action for this casting.

 Subtle Spell: When the yuan-ti casts a spell, it can spend 1 sorcery point to cast it without any somatic or verbal components.

Multiattack (Yuan-Ti Form Only). The yuan-ti makes two ranged attacks or two melee attacks, but can constrict only once.

Bite (Snake Form Only). Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 5 (1d4 + 3) piercing damage plus 7 (2d6) poison damage and the creature has disadvantage on the saving throw it makes to maintain its concentration.

Constrict. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) bludgeoning damage, and the target is grappled (escape DC 16) and if it is a creature, it has disadvantage on the saving throw it makes to maintain its concentration. Until this grapple ends, the target is restrained, and the yuan-ti can't constrict another target.

Longsword (Yuan-ti Form Only). Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 7 (1d8 + 3) slashing damage, or 8 (1d10 + 3) slashing damage if used with two hands, and the creature has disadvantage on the saving throw it makes to maintain its concentration.

Longbow (Yuan-ti Form Only). Ranged Weapon Attack: +5 to hit, range 150/600 ft., one target. Hit: 6 (1d8 + 2) piercing damage plus 7 (2d6) poison damage and the creature has disadvantage on the saving throw it makes to maintain its concentration.