Lead

Leashes are items used to hitch animals to fence posts or nether brick fence posts, and also to lead them around.

Usage
Right-clicking with a leash in your hand will tie it on the animal that you are facing.

Most passive mobs can be "leashed". This includes pigs, chickens, cows, horses, sheep, squids, Iron Golems, Snow Golems, and wolves. The Bat and Villagers are the only passive mobs which cannot be leashed. Note that leashed mobs that naturally despawn (like squids) still despawn. If leashed animals are ten or more blocks away from the player leashing them, the leash will "snap" and turn into the item.

Trivia

 * The leash can extend out to 5 blocks when tied between a fence post and a mob

Gallery
Leine 拴绳