Spellcasting. The giant casts one of the following spells, requiring no material spell components and using Charisma as the spellcasting ability (spell save DC 17):

At will: meld into stone, move earth, spider climb

Multiattack. The giant makes two Warhammer attacks.

Warhammer. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 16 (2d8 + 7) or or 18 (2d10 + 7) bludgeoning damage.

Warhammer (Unfurled Might). Melee Weapon Attack: +13 to hit, reach 10 ft., one target. Hit: 20 (2d10 + 9) bludgeoning damage.

Rock. Ranged Weapon Attack: +11 to hit, range 60/240 ft., one target. Hit: 21 (3d10 + 7) bludgeoning damage.

Rock (Unfurled Might). Ranged Weapon Attack: +13 to hit, range 60/240 ft., one target. Hit: 31 (4d10 + 9) bludgeoning damage.

Tunnel Scream (1/Day). The maur screams within a stone enclosure, from tunnel to building. Each creature within a 60 ft. cone in front of the Maur must make a DC 17 Constitution saving throw, taking 35 (10d6) thunder damage, becoming deafened for 1 minute and stunned until the end of the maurs next turn on a failed save, or half as much damage, ignoring the stunned and deafened effects, on successful one.

Unfurled Might (1/Day). Can only be used when in a space that's at least 20 ft. high and 15 ft. wide. When this action is used the Maur becomes resistant to all damage for 1 round and for the following 1 minute gains the following benefits:

• It's size changes to Huge, it's melee reach increases by 5 ft.
• It gains 20 temporary hit points and immunity to Lightning damage
• Any checks, saves and attack rolls relying on strength receive a +2
• Wisdom, Intelligence and Charisma saving throws are made with advantage
• It can cast call lightning and chain lightning once each, using Charisma as the spellcasting ability (spell save DC 17)