Clockwork Titan

Immutable Form. The clockwork titan is immune to any spell or effect that would alter its form.
Magic Resistance. The clockwork titan has advantage on saving throws against spells and other magical effects.
Magic Weapons. The clockwork titan's weapon attacks are magical.
Tower. The clockwork titan can embark up to one medium-sized creature on the top of its head. This is usually the place from where its creator commands it in combat while casting spells.
Antimagic. Anytime the clockwork titan – or any creature on top of its head – is targeted by a magic missile spell, a line spell, or a spell that requires a ranged attack roll, roll a d6. On a 1 to a 4, the clockwork titan – or the targeted creature – is unaffected.
Siege Monster. The clockwork titan deals double damage to objects and structures.

Multiattack. The clockwork titan makes three slam attacks.
Slam. Melee Weapon Attack: +17 to hit, reach 15 ft., one target. Hit: 32 (4d10 + 10) bludgeoning damage.
Ground Blast (Recharge 6). The clockwork titan strikes the ground with its leg, creating powerful columns of magic erupting from the land around it. All other creatures on the ground within 60 feet of the titan take 65 (10d12) force damage and must succeed on a DC 25 Strength saving throw or be ejected 30 feet into the air.