Which viper has a tail tip that resembles a spider used as a lure?

The spider-tailed horned viper has a tail tip that resembles a spider and uses it as a lure.

Its scientific name is Pseudocerastes urarachnoides, and it is a venomous viper native to western Iran and nearby parts of Iraq. The tail ends in a bulb-like structure surrounded by long, drooping scales. Together, these features create a convincing spider-like appearance.

The viper waves the tail in a distinctive figure-eight motion, exploiting the hunting instincts of insect-eating birds. When a bird approaches what appears to be prey, the concealed snake can strike. This behavior is called caudal luring, and field observations have shown that tail movement increases when birds are nearby.

The species was especially mysterious when an unusual specimen collected in 1968 was mistakenly identified as a Persian horned viper; its strange tail was blamed on a parasite, deformity, or tumor. A later specimen led scientists to formally describe the species in 2006. Other snakes lure prey with their tails, but none has quite the same spider-like ornamentation.