List of animals with the most unusual horn.
A horn is a pointed projection of the skin on the head of various mammals, consisting of a covering of horn (keratin and other proteins) surrounding a core of living bone. True horns are found only among the ruminant artiodactyls, in the families Antilocapridae and Bovidae. These animals have one or occasionally two pairs of horns, which usually have a curved or spiral shape, often with ridges or fluting. In many species only the males have horns. Horns start to grow soon after birth, and continue to grow throughout the life of the animal (except in pronghorns, which shed the outer layer annually, but retain the bony core).
One creature with the weirdest horn in the world is a bull named Lurch. According to the Guinness Book of Records, he is the bull with the largest horn circumference in the world, measuring 37.5 inches