Increase one ability score by 1 and a different ability score by 2 

You have Darkvision out to a range of 60 feet 

 You have a natural Bite attack that deals 1d6 Piercing damage + Strength.

You have a natural Constrict attack that deals 1d6 Bludgeoning + Strength. If you successfully hit a target with this
attack, the target is grappled and restrained. You may only constrict one target at a time and your speed is reduced to 0 while
constricting the target. Your tail can act as a free hand to grab and hold items.

Starting at 3rd level you can cast the spell Command using Charisma as your spellcasting once per long
rest. Starting at 5th level you can cast the spell Dominate Person using Charisma as your spellcasting once per long rest.

You have advantage against spells and other magical effects

Yuan-Ti Abomination can read, write and speak Common, Draconic and Abyssal. Additionally Yuan-Ti Abomination
can speak with and understand snakes.