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.

Innate Spellcasting (Yuan-ti Form Only). The yuan-ti’s innate spellcasting ability is Charisma (spell save DC 12). The yuan-ti can innately cast the following spells, requiring no 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.

Spellcasting (Yuan-ti Form Only). The yuan-ti is an 8th-level spellcaster that uses Wisdom as its spellcasting ability (spell save DC 13; +5 to hit with spell attacks). It knows the following spells from the ranger spell list:

1st Level (4 slots): cure wounds, fog cloud, hunter’s mark

2nd Level (3 slots): pass without trace, spike growth

Ranger’s Companion. The yuan-ti has a pet flying snake, it moves and acts on the yuan-ti’s turn, and the yuan-ti can use a bonus action to command it to take the Dash, Dodge, Disengage, or Attack action. The yuan-ti can also command it to Attack as part of the yuan-ti’s Multiattack action (see below). The flying snake can take only one action on each of the yuan-ti’s turns.

Multiattack (Yuan-ti Form Only). The yuan-ti makes two ranged attacks or two melee attacks and can command it’s flying snake to move up to its fly speed and use its Bite action, but the yuan-ti can use its constrict attack only once each.

Bite (Snake Form Only). Melee Weapon Attack: +5 to hit, reach 5 ft., one creature. Hit: 7 (1d4 + 3) piercing damage plus 7 (2d6) poison damage.

Constrict. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 (2d6 + 3) bludgeoning damage, and the target is grappled (escape DC 13). Until this grapple ends, the target is restrained, and the yuan-ti can’t constrict another target.

Scimitar (Yuan-ti Form Only). Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) slashing damage.

Longbow (Yuan-ti Form Only). Ranged Weapon Attack: +5 to hit, range 150/600 ft., one target. Hit: 7 (1d8 + 3) piercing damage plus 10 (3d6) poison damage.