Citrupine

Ambush Predator. The Citrupine may be hiding in the ground when encounter. It will attempt to lunge out, giving it 1 free bite attack and advantage on its Initiative roll.

Beastly Nature. Citrupine are Beasts and so their minds function purely on instinct. Because of this, they automatically fail all Intelligence saving throws and are unable to make/automatically fail Intelligence(Arcana), Wisdom(Insight, Animal Handling) and Charisma(Deception, Persuasion) checks unless otherwise specified. The Citrupine has a base Perception of 10 + Proficiency Bonus, a base Investigation of 7 and a base Survival of 10 + Proficiency Bonus. Neither the Citrupine's Intelligence score, nor their Wisdom score can be increased by any means. They are unaffected by Awaken or any similar spell. The Citrupine has immunity to the Charmed condition and resistance to Psychic damage.

Ice Walk. The Citrupine can move across and climb icy surfaces without needing to make an ability check. Additionally, difficult terrain composed of ice or snow doesn't cost it extra movement.

Dig. The Citrupine attempt to dig into the ground. On its first turn, it only burrows 5ft, but moves 10ft after that.

Bite. Melee Weapon Attack: +4 to hit, reach 5 ft., 1 target. Hit: 7 (2d4 + 2) Necrotic damage (because when I asked my D&D chat what damage type mandibles would do, bludgeoning, piercing or slashing, the first response  I got was Necrotic, I hope your happy). 

Citrupine Acid. (Recharge every 2 rounds):  range 10ft., 2 targets. The target creature(s) must succeed a DC 13 Constitution saving throw or take 7 (1d4 Acid and 1d6  + 1 Cold) damage and have their movement speed reduced by 5ft, or 3 (1d6 + 1) Cold damage on a failed save. 

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