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.