Razorvine

From Dungeon Master's Guide, page 110.

Wilderness hazard

Razorvine is a plant that grows in wild tangles and hedges. It also clings to the sides of buildings and other surfaces as ivy does. A 10-foot-high, 10-foot-wide, 5-foot-thick wall or hedge of razorvine has AC 11, 25 hit points, and immunity to bludgeoning, piercing, and psychic damage.

When a creature comes into direct contact with razorvine for the first time on a turn, the creature must succeed on a DC 10 Dexterity saving throw or take 5 (1d10) slashing damage from the razorvine's bladelike thorns.