Barrel Crab MKII

Lightning Empowered Construct. The Barrel Crab MKII has resistance to lightning, slashing and piercing damage. It also has immunity to poison, psychic and necrotic damage.

Walker Manoeuvrability. The Barrel Crab MKII ignores movement penalties from moving across difficult terrain. However its cumbersome size means that it cannot take any climbing actions

Multiattack. The Barrel Crab MKII can make two melee attacks using its Claws. 

Claw. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 5) slashing/bludgeoning damage, and the target is grappled (escape DC 12). The Barrel Crab MKII has two claws, each of which can grapple only one target. If a claw is grappling a target, it may only attack that target. At the start of each of its turns, a grappled target may attempt to escape.

Lightning Death Cannon. Ranged Weapon Attack: +6 to hit, range 100/300 ft., target area. Hit:  23 (4d10 + 3) lightning damage.,Reload (1). All targets within 5 ft of target area must make a DC 12 dexterity saving throw. On a success, they take half damage. The Barrel Crab MKII cannot target areas within 5 ft of itself using the cannon.

Repair (3/Day). The Gnomish Artificers crewing the Barrel Crab MKII restore 2d8 + 4 hit points to it. 

Engine Overcharge. As a bonus action, The Barrel Crab MKII engines are pushed to the limit! The Barrel Crab MKII takes 2d6 fire damage and gains an extra action for the turn. Each subsequent use of Engine Overcharge increases the damage taken by 1d6. This extra damage is reset when the Barrel Crab MKII completes a long rest.

Absorb Elements (3/long rest). When the Barrel Crab MKII receives acid,cold, thunder, fire or lightning damage, its crew of Gnomish Artificers can cast absorb elements as a reaction.