Kani Pearl (カニパール) is the second boss in Sonic Labyrinth, awaiting Sonic at the bottom of a long, Ring-filled slope in Act 4 of Labyrinth of the Sea. The first half of its name, "kani", is the Japanese word for "crab".
The boss arena here is a sloping E-shape. Sonic is first beset by waves of miniature crab Badniks crawling down the inclines, but they are easy enough to avoid simply by Spin Dashing all over the place. When Kani Pearl finally materializes, the mechanical crustacean (in true crabby fashion) simply scuttles sideways back and forth along the upper level. Impervious to damage while its shell is closed, the boss should be attacked when it flips open its armor to fire a pearly bullet in Sonic's direction.
Five hits blows it up, allowing Sonic to grab the Chaos Emerald.