Poisonous Snake is a Tiny beast with unaligned alignment and Challenge Rating 1/8 in the 2014 SRD. This stat block includes AC 13, 2 hit points, speeds, traits, and actions.
Bite - Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 1 piercing damage, and the target must make a DC 10 Constitution saving throw, taking 5 (2d4) poison damage on a failed save, or half as much damage on a successful one.