Impenetrable Skin. The beast has a super hard natural armor that makes it harder than anything known to man. If a creature makes a failed attack on the beast then the creature must make a STR saving throw (DC 10). On a failed saving throw the creatures weapon loses durability. After three failed saves the weapon will break.

Soft Spot. The beast has one spot on it that is not impenetrable and that is the spot that can be attacked and used to deal damage to the beast.

Multiattack. The beast makes two attacks: one with its bite and one with its smash. It can't make both attacks against the same target.

Bite. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 33 (4d12 + 7) piercing damage. If the target is a Medium or smaller creature, it is grappled (escape DC 17). Until this grapple ends, the target is restrained, and the Beast can't bite another target.

Smash. Melee Weapon Attack: +10 to hit, reach 40 ft., one target. Hit: 60 (9d8 + 7) bludgeoning damage. If the target is within 30 ft. of the smash then make a DEX saving throw (DC 18) or suffer 5d6 bludgeoning damage.