Monster Manual p.265
Heated Body. A creature that touches the snake or hits it with a melee attack while within 5 feet of it takes 3 (1d6) 1d6 fire damage.
Multiattack. The snake makes two attacks: one with its bite and one with its tail. Bite. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d4 + 1) 1d4+1 piercing damage plus 3 (1d6) 1d6 fire damage. Tail. Melee Weapon Attack: +3 to hit, reach 5 ft., one target. Hit: 3 (1d4 + 1) 1d4+1 bludgeoning damage plus 3 (1d6) 1d6 fire damage.