You are a Beast.

You are Medium or Small. You choose the size when you select this race.

Your walking speed is 20ft.
Your burrowing speed is 10ft.
Your swim speed is 30ft.
Your climbing speed is 20ft.

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 discern colors in that darkness only as shades of gray.

You have advantage of ability checks that relies on the sense of smell. (Perception Investigation and Insight)

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 have Tremor sense out to a range of 15ft.

You can hold your breath for 15 minutes.

You lunge at a foe, biting them with your fangs. Make a melee attack. On a hit the target take 1d6+ your proficiency bonus poison damage and must make a Constitution saving throw. On a fail the target has the Poisoned condition until the end of its next turn. 
This attack's damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).