Two Heads. The amphisbaena has advantage on Wisdom (Perception) checks and on saving throws against being blinded, charmed, deafened, frightened, stunned, and knocked unconscious.
Multiattack. The amphisbaena makes two bite attacks.
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit:6 (1d4 + 4) piercing damage, and the target must make a DC 11 Constitution saving throw, taking 3 (1d6) poison damage on a failed save, or half as much damage on a successful one.
Found in Danger at Dunwater, these strange reptiles have a head at either end of their serpentine bodies, each one equipped with venomous fangs. To move, an amphisbaena uses one head to grip the neck of its other head, forming a hoop that rolls over the ground.