An adorable puppy with a tail growing out of his forehead has gone viral.

The ten-week-old Beagle Terrier mix named "Narwhal the Little Magical Furry Unicorn" was abandoned but has found a home in Mac’s Mission shelter in Missouri.

Vets believe that the extra tail sticking out of his face is from a parasitic twin.

Parasitic twins occur when a twin embryo begins to develop but not fully, and the pair does not separate.

Narwhal's extra tail does not wag, but his carers said that he will keep it.

They dog home said: "We are not accepting applications for him right now until we are very certain his unicorn horn is not going to have a growth spurt and become an issue."

Narwhal will be up for adoption once the shelter has determined that the extra tail will not cause problems for him down the road.

An adorable puppy from Missouri is called "unicorn" by carers because of a horn-like tail attached on his forehead. Ten-week-old Beagle Terrier mix Narwhal was abandoned but has found a home in Mac’s Mission shelter. Vets believe that the extra tail sticking out of his face is from a parasitic twin. Parasitic twins occur when a twin embryo begins to develop but not fully, and the pair does not separate. Narwhal's extra tail does not wag, but his carers said that he will jeep it. They dog home said: "We are not accepting applications for him right now until we are very certain his unicorn horn is not going to have a growth spurt and become an issue." Narwhal will be up for adoption once the shelter has determined that the extra tail will not cause problems for him down the road.
Credit: Mac the Pit bull.