Multiattack. The giant makes two Thundering Stone Club or Boulder attacks in any combination.

Thundering Stone Club. Melee Weapon Attack: +10 to hit, reach 15 ft., one target. Hit: 16 (3d6 + 6) bludgeoning damage. The giant can cause the club to emit a burst of thunderous energy that deals 10 (3d6) thunder damage to each creature, other than the giant, within 30 feet of the target. The club can emit a burst this way only once per turn.

Boulder. Ranged Weapon Attack: +10 to hit, range 60/240 ft., one target. Hit: 19 (3d8 + 6) bludgeoning damage, and the target must succeed on a DC 18 Strength saving throw or have the prone condition. After the giant throws the boulder, roll a d6; on a roll of 3 or lower, the giant has no more boulders to throw.

Unyielding. In response to failing a saving throw to avoid being moved, having the prone condition, or both, the giant succeeds instead.