Legendary Resistance (3/Day). If Kogla fails a saving throw, he can choose to succeed instead.

Siege Monster. Kogla deals double damage to objects and structures.

Multiattack. Kogla makes two fist attacks.

Fist. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 23 (3d10 + 7) bludgeoning damage. The target is pushed 5 feet away from Kogla. 

Rock. Ranged Weapon Attack: +11 to hit, range 50/100 ft., one target. Hit: 31 (7d6 + 7) bludgeoning damage.

Rescue (Recharges after a Short or Long Rest). Kogla picks up its bonder if its within 10 feet. Kogla then moves up to 40 feet and can move through the space of any creature smaller than huge. Neither Kogla nor its bonder provoke attacks of opportunity during this move.

Fling. One Large or smaller object held or creature grappled by Kogla is thrown up to 60 feet in a random direction and knocked prone. If a thrown target strikes a solid surface, the target takes 3 (1d6) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 14 Dexterity saving throw or take the same damage and be knocked [condition]prone[condition].

Kogla can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. Kogla regains spent legendary actions at the start of its turn.

Determined (Costs 2 Actions). Kogla can only use this action if it's bonder is within 120 ft. of it. Kogla recovers 25 hit points.

Grapple. Kogla makes a fist attack. If the target is medium or smaller it must succeed on a DC 14 Dexterity saving throw or be grappled (escape DC 19).