One score increases by 1, one score increases by 2.

Yuan-Ti mature at the same rate as humans and have lifespans similar in length to theirs.

Your size is medium.

Your base walking speed is 30 feet.
Swim speed of 20 in halfblood form.

You can see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.

You know the Poison Spray cantrip. You can cast Animal Friendship an unlimited number of times with this trait, but you can target only snakes with it. Starting at 3rd level, you can also cast Suggestion with this trait. Once you cast it, you can't do so again until you finish a long rest. You can also cast it using any spell slots you have of 2nd level or higher.

You have advantage on saving throws against spells and other magical effects.

You have advantage on saving throws you make to avoid or end the poisoned condition on yourself. You also have resistance to poison damage.

You can speak, read, and write Common and one other language.

As an action, you may change your form from Halfblood to Purebreed or vice versa.
Upon transformation, your Strength and Dexterity swap. And your spellcasting ability score (Intelligence, Wisdom or Charisma) and your Constitution swap.
To transform from a Halfblood into a Purebreed you must eat mammalian meat.
To transform into a Purebreed into a Halfblood you must eat reptilian meat.
If transforming more than twice before a long rest, roll a wisdom saving throw. On a fail, gain a point of exhaustion.