Binacle's body resembles a hand. The "arm" is orange with a single white stripe and can stretch and contract at will. The "hand" is brown with three long claws and a face on the "palm" with two round eyes with black pupils, orange puffy cheeks, and no visible mouth. Binacle always live in pairs on one gray rock, when they fight, one of them will move to a different rock. It eats seaweed that washes up on the shoreline.
Binacle made its main series debut in Unlocking Some Respect!, with each of Binacle's two bodies being under the ownership of two people. Locke owned one half, which he calls "Lefty" and his mentor Ed owned the other half, which he calls "Righty".
Binacle seems to be based on the goose barnacle, due to their general shape and use of a connective "stalk" to cling to rocks. Considering it survives together with a second Binacle, it may possibly be a reference to the rarer, same species symbiosis. Considering its hand-like body, and its eyes within its "palms", Binacle may have also been based on the hamsa.
Binacle is a combination of the prefix bi- (meaning two) and barnacle. It may also refer to the nautical instrument which held a ship's compass known as a binnacle. It may also be derived from knuckle, referring to its hands and making the name a pun.
Kametete may be a combination of 亀の手 kame no te (Japanese goose barnacle), tête (French for head), and 手 te (hand).