16 (natural armor)
58 (9d8+18)
walk 30 ft.
poison; bludgeoning, piercing, slashing from nonmagical attacks that aren't adamantine
charmed, exhaustion, frightened, paralyzed, petrified, poisoned
darkvision 60 ft.
understands one language of its creator but can't speak
5
The oaken bolter has advantage on saving throws against spells and other magical effects.
The oaken bolter makes two lancing bolt attacks or one lancing bolt attack and one harpoon attack.
Melee or Ranged Weapon Attack: +7 to hit, reach 5 ft. or range 100/400 ft., one target. Hit: 15 (2d10 + 4) piercing damage.
Ranged Weapon Attack: +7 to hit, range 50/200 ft., one target. Hit: 9 (1d10 + 4) piercing damage, and the target is grappled (escape DC 12). While grappled in this way, a creature's speed isn't reduced, but it can move only in directions that bring it closer to the oaken bolter. A creature takes 5 (1d10) slashing damage if it escapes from the grapple or if it tries and fails. As a bonus action, the oaken bolter can pull a creature grappled by it 20 feet closer. The oaken bolter can grapple only one creature at a time.
The oaken bolter launches an explosive charge at a point within 120 feet. Each creature within 20 feet of that point must make a DC 15 Dexterity saving throw, taking 17 (5d6) fire damage on a failed save, or half as much damage on a successful one.