Survival in New Vance

Reaction, which you take when a hostile creature moves within 15 feet of you. You trigger the rapid expansion of a network of specialized, fast-growing fungi you've cultivated in the surrounding terrain. The triggering creature must make a Dexterity saving throw. On a failed save, the creature takes 4d8 bludgeoning damage and their movement speed is reduced to 0 until the end of its next turn as it becomes entangled in the dense fungal growth. On a successful save, the creature takes no damage and its speed is halved until the end of its next turn. The fungal growth withers away after 1 round.