Scraplungs. The crab can hold its breath without suffocating for up to one hour.

Scrapphibious. The crab can breathe air and water.

Scrap burrow. The crab can burrow through scrap and light floors like wood, dirt or sand while doing so it gets stealth expertise.

Scrap from below. While in water or underground, the crab's attacks deal an additional 1d8 bludgeoning damage, has a bonus of +8 to dexterity saving throws and expertise in stealth.

Scrapclad Ambush. In the first round of a combat, the crab has advantage on attack rolls against any creature it has surprised and gains one additional action.

Scrapshell. A Creature that attacks the Crab while within 10 feet of it takes 1d6 slashing damage.

Scrapjab. Melee Weapon Attack: +7 to hit, reach 20 ft. Hit 2d6+8 piercing damage.

Scrapswipe. Melee Weapon Attack 10 ft cone: +7 to hit, reach 10 ft. Hit 2d4+6 slashing damage.

Scrap grab and graft. Melee Weapon Attack (3/day 5-6 Recharge): +10 to hit, reach 10ft, one target. Hit 1d8+4 slashing damage plus 2d8+6 bludgeoning damage. The crab will adorn itself with worn metal of the attacked getting a +2 to its ac, while the attacked gets a -2 to his ac for this combat.

Scrap retreat. The crab can retreat in its shell to gain a +10 ac bonus at the cost of losing all its movement points for this and the next turn. The Crab cant do opportunity attacks while in this state. This ability cant be used if more than halve its movement speed has been used.

Scrapback. If attacked while flanked every creature flanking it in a 10 ft radius needs to roll a dc18 dexterity saving throw. On a failed save they take 3d8 bludgeoning damage and become prone.