Draconic Serpent

Keen Smell. The draconic serpent has advantage on Wisdom (Perception) checks that rely on smell.

Stealthy Predator. The draconic serpent can take the Hide action as a bonus action on each of its turns.  It may attempt to Hide even when only in dim light or when lightly obscured by foliage, heavy rain, falling snow, mist, and other natural phenomena.

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 17 (5d4 + 4) piercing damage. If the target is a creature, it must succeed on a DC 16 Constitution saving throw or be paralyzed for 1 minute. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success

Stunning Screech (Recharge 5-6). The draconic serpent emits a horrific screech. Each creature within 30 feet of it that can hear it must succeed on a DC 16 Constitution saving throw or be stunned until the end of the draconic serpent's next turn.