Bloodied: At half health (75 hp) the usima can now use lightning bolt as one of its multi attacks. As well as this, its fist attacks increase to 3d6.
Multi-attack: The usima can make two attacks with its fists in one turn. These can be Grapple or punch attacks. Grapple: The usima can choose to grapple a creature with its fists. The creature has advantage on attack rolls against a creature it is grappling. It can use its action to try to pin a creature grappled by it. To do so, it must make another grapple check. If it succeeds, it and the creature are both restrained until the grapple ends. Punch: The usima Melee Weapon Attack: +9 to hit, one target. Hit:(2d6+7) bludgeoning damage. Swipe: The usima swings its fist, swiping at the ground in a 15 ft cone. Each creature in that area must make a DC 19 Dexterity saving throw, taking (4d8+7) bludgeoning damage and fall prone on a failed save, or half as much damage on a successful one. Lightning Beam: Lightning crackles around the usima's horns, causing static charge to generate and sending an explosive bolt of lightning at a point it choose within a range of 90 ft. Each creature in a 15 ft sphere centered on that point must make a DC 15 Dexterity saving throw, taking (4d10+10) fire damage on a failed save.