Dipsa

Swamp Stealth. The dipsa gains an additional +2 (+9 in total) to Stealth in swamp terrain.

Amorphous. The dipsa can move through a space as narrow as 1 inch wide without squeezing.

Discreet Bite. The bite of a dipsa is barely perceptible and the wound is quickly anesthetized. A creature bitten must succeed on a DC 15 Wisdom (Perception) check to notice the attack or any damage taken from it.

Translucent. The dipsa can take the Hide action as a bonus action on each of its turns.

Bite. Melee Weapon Attack: +7 to hit, reach 0 ft., one creature in the dipsa's space. Hit: 1 piercing damage, and the dipsa attaches to the target. A creature with a dipsa attached takes 3 (1d6) acid damage per round per dipsa, and it must make a successful DC 12 Constitution saving throw or have its hit point maximum reduced by an amount equal to the damage taken. If a creature's hit point maximum is reduced to 0 by this effect, the creature dies. This reduction to a creature's hit point maximum lasts until it is affected by a lesser restoration spell or comparable magic.