Immutable Form. The construct is immune to any spell or effect that would alter its form.

Magic Resistance. The construct has advantage on saving throws against spells and other magical effects.

Pilot Needed. This construct is a mech. It requires a creature of small to medium size to operate. The pilot must make a DC 16 Intelligence check to operate.

Last Resort.  Upon reaching 0 hit points, the top hatch of the mech will open,cast Feather Fall on the pilot, and launch the pilot 40ft in the air. After this, the mech will detonate its magical motor in a 20ft sphere, dealing 6d6 Thunder damage and 1d4 physcic damage. The mechs exterior is unharmed besides any damage taken.

Multiattack. The mech makes two melee attacks.

Stomp. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 20 (3d8 + 7) bludgeoning damage.

Flamethrower (Recharge 6). The mech shoots scorching flames  in a 15-foot cone. Each creature in that area must make a DC 17 Dexterity saving throw, taking 30 (7d8) fire damage on a failed save, or half as much damage on a successful one.

Explosive (Recharge 5). The mech launches a bomb in a arc toward a target location up to 120 feet away. The bomb detonates at the start of the mech's next turn. Explosion is in a 20ft sphere and deals 5d6 force damage, 1d6 thunder damage, and 2d6 fire damage.