Caribou Pirates

The Caribou Pirates are a crew who arrived at Sabaody Archipelago around the same time as the Straw Hats were reuniting. Their captains are the brothers Caribou and Coribou, which temporarily changed to Demalo Black when they joined the fake Straw Hat crew, under the belief they were real until the truth was disclosed.

History
The Caribou Pirates became famous through their two captains killing many Marines. They eventually joined the Impostor Straw Hat Pirates, but had no intention of truly following them. Instead, Caribou planned to kill them from the inside. After discovering that the crew they joined were fakes, the Caribou Pirates buried the impostors (without Black, Cocoa, and fake Chopper, all of whom were captured) alive and then set sail, using their coated ship to follow behind the Thousand Sunny and the real Straw Hat Pirates.

When Caribou hopped on board of the Sunny, Mohmoo, the one carrying the Caribou Pirates' ship, fled in terror at the sight of his old enemies: Nami, Luffy, and Sanji. This separated the Caribou Pirates from their captain. Shortly after this, the rest of the Caribou Pirates forced Mohmoo to bring them back to rescue Caribou. As they approached the Sunny once again, they screamed out loud that they would save Caribou, only for the giant Kraken to grab their ship and crush it in one snap, popping their protective bubble coating and leaving the crew to float in the sea, possibly drowning or being crushed by the pressure. This left their captain (and Mohmoo, who escaped) the only one alive, being on board the enemy's ship, until he managed to escape captivity and is currently hunting mermaids on Fishman Island.

Crew Strength
The crew is presumably strong, as both their captains are considered to possess the highest bounties in the new generation of rookies around the time when the Impostor Straw Hat Pirates were recruiting at the Sabaondy Archipelago. Their captain's possession of a Logia-class Devil Fruit also makes him a dangerous opponent. Having managed to make it through the first half of the Grand Line is something impressive. Out of Black's assembled recruits, they were the only ones to escape capture, while dragging the remaining impostors with them.

Ship
Their vessel appears to be somewhat larger than the Thousand Sunny and has a figurehead of a caribou, a play on their captain's name. It was seen being pulled by the sea cow Mohmoo when the crew tried to attack the Straw Hat Pirates, explaining how it managed to catch up to them so quickly. Caribou called it "advanced sea navigation". However, this can also be a downside as Mohmoo fled from the Straw Hats in fear, while dragging the rest of the Caribou Pirates against their will. Later the crew managed to regain control of Mohmoo with a strike to its head, in order to have it carry them back to the Thousand Sunny in order to save their captain, but the Kraken easily destroys the ship.

Other Information
Most of the crewmates seem to resemble Coribou, being fat with chubby faces, but with thin arms and legs. They wear dark pants, with a light unbuttoned shirt and a small dark colored top hat. Given their captain's penchant for burying his opponents alive, his subordinates (Coribou included) seem to primarily function as grave-diggers, digging graves for enemies that Caribou wishes to bury.