Boulder Creep

Actions

Bite. Melee Weapon Attack: +5 to hit, reach 5 ft., one target. Hit: 10 1d6+3 slashing damage and inflicting Insect Poison. If the target is a Large or smaller creature, it is grappled (escape DC 13). Until this grapple ends, the boulder creep can bite only the grappled creature and has an advantage on attack rolls to do so.   Poison Spray (Recharge 6). The boulder creep spits acid in a line that is 30 feet long and 5 feet wide, provided that it has no creature grappled. Each creature in that line must make a DC 13 Dexterity saving throw, suffer from Insect Poison on a failed save, or 1d6 on a successful one.   Insect Poison: The victim takes 1d6 poison damage over the course of 3 turns.

A huge roach-like insect with a giant boulder as its carapace.

Forests, overgrown ruins.