Muck covers this muscular snake, which seems more at home in the silt and water on the ground than among tree boughs.

Earth Elemental Ancestry. Formerly native to the Plane of Earth, quickserpents migrated to the Material Plane centuries ago because of a catastrophe that destroyed the area of the plane where they laired. The catastrophe also shunted the surviving serpents to swamps with connections to the Plane of

Earth. The creatures adapted to their new environments and lost many of their elemental traits. They still understand the language of earth elementals and typically avoid attacking the elementals. A handful of powerful elementals that remember the snakes have attempted to reintegrate them to the Plane of Earth with mixed results.

Ambusher from Below. A quickserpent, like many terrestrial constrictor snakes, ambushes its prey. However, it waits below the surface where it picks up the vibrations of creatures traveling above it. If the terrain is suitable, the serpent churns the ground into quicksand to pull unsuspecting prey into the earth. While its victim struggles to escape the mire, the serpent takes advantage of its prey’s helplessness to wrap itself around and crush its prey. If the serpent manages to ensnare more than one creature, it targets the one with the most success emerging from the quicksand.

Quickserpent

Large beast, unaligned
Armor Class 15 (natural armor)
Hit Points 102 (12d10 + 36)
Speed 40 ft., burrow 20 ft., climb 20 ft.

STR	DEX	CON	INT	WIS	CHA
20 (+5)	12 (+1)	17 (+3)	5 (-3)	14 (+2)	7 (-2)

Skills Stealth +3
Senses tremorsense 60 ft., passive Perception 12
Languages understands Terran but can’t speak
Challenge 4 (1,100 XP)

Swamp Camouflage. The quickserpent has advantage on Dexterity (Stealth) checks made to hide in swampy terrain.

Actions

Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 8 (1d6 + 5) piercing damage.

Constrict. Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 14 (2d8 + 5) bludgeoning damage, and the target is grappled (escape DC 15) if it is Large or smaller. Until this grapple ends, the creature is restrained, and the quickserpent can’t constrict another target.

Quicksand Pit (Recharge 5-6). The quickserpent turns a 10-foot cube of natural mud or loose stone into a pit of quicksand. Each creature in the area when the quickserpent creates the pit must succeed on a DC 15 Dexterity saving throw or sink 1d4 feet into the quicksand and become restrained. A creature that successfully saves moves to the pit’s edge as it is formed. A creature that enters the quicksand for the first time on a turn or starts its turn in the quicksand it sinks 1d4 feet and is restrained. A creature that is completely submerged in quicksand can’t breathe.

A restrained creature can try to escape by taking an action to make a DC 15 Strength check. On a success, the creature escapes and enters a space of its choice within 5 feet of the edge of the quicksand. A creature within 5 feet of the quicksand can take an action to pull a creature out of the quicksand. Doing so requires a successful DC 15 Strength check, and the quickserpent has advantage on attack rolls against the creature until the end of the creature’s next turn.