Anaclet Shotgun is an unofficial English name (along with Anaclet Weasel) corresponding to the character called Anacleto Faina or Anacleto Mitraglia in the original Italian, a male anthropomorphic dog.
The conniving Anaclet Shotgun is Donald Duck's nextdoor neighbor. Shotgun is every bit as antagonistic as Donald's other neighbor, Jughead Jones, and both Jones and Shotgun tend to get mad at small things, or just bother Donald for the sake of it. However, where Jones will often use strength, Anaclet Shotgun, who has the thin frame, bowler hat and thin black mustache of the typical melodrama villain, will mostly use tricks and gadgets. Anaclet Shotgun has a nephew called Cashew who is a classmate of Huey, Dewey and Louie Duck.
Behind the scenes
Created in 1965 by respected Italian cartoonists Rodolfo Cimino and Giovan Battista Carpi, Anaclet Weasel is just as recurring a character in Italy as Neighbor Jones is in the U.S.A. and in Scandinavian countries. In spite of appearing in more than a hundred stories, he has never appeared in an English publication so far.
Interestingly enough, Anaclet seems to derive from a misrepresentation of Jones, as the name "Anacleto Mitraglia" was first found as Jones' name in early Italian translations of American stories before the character was given a widely different design (and, to an extent, personality) by various Italian artists. For a while, his Italian name varied between "Faina" and "Mitraglia" as his last name, though "Mitraglia" eventually came out winner.
The former name, "Faina", actually refers to a type of weasel, leading to the character's last name in his alternate English moniker. This is in spite of Anaclet not actually being an anthropomorphic weasel at all, but actually a dog, although it is possible he has some weasel ancestry on his father's side drowned out in dog blood.
The latter name, "Mitraglia", translates to "machine gun" or "ammunition", hence "Shotgun" as the character's current unofficial English moniker.