176-176, who wears the serial number 176-167, is a male anthropomorphic dog
176-176 is one of the main Duckburg Beagle Boys who usually cannot be distinguished from one another (though he is seemingly the youngest of that particular bunch of siblings). With them, he committed numerous crimes, mostly revolving around the Beagles' goal of robbing Scrooge McDuck's Money Bin.
In 2003, he suddenly fell in love with Emily Quackfaster, Scrooge's middle-aged endlessly-resourceful secretary. Emily came to return his affections and began dating him, making him promise to forswear his life of crime and villainy. The two had a brief but blissful romance, which was cruelly terminated by Blackheart Beagle's greedy schemings; Blackheart and two of 176's brothers tricked 176-176 into using his relationship with Miss Quackfaster to get into the Money Bin.
They succeeded in taking out several billion dollars, and Miss Quackfaster, at first, refused to believe 176-176 had not arranged the whole thing with his brothers from the start, tricking her into a false romance just for the burglary's sake. In an attempt to make things right, 176-176 stole the money back from his brothers and brought it back to Emily, for her to take back to the Bin. He left a note wherein he explained that he could neither ask her to trust him after this blunder, nor fully forgive her for judging him so quickly, but that she would always have a spot in his heart; it seemed clear enough that the feeling was mutual.
Following this misadventure, 176-176 reintegrated the ranks of the regular Beagle Boys and returned to crime, though his heart was ever after not into it whenever he had to attack the Money Bin in the presence of Miss Quackfaster.
Behind the scenes
As demonstrated by Deadhead-167 who is obviously not the usual 176-167, Beagle Boys can sometimes share or switch prison numbers. Thus, it cannot be said for sure that this particular 176-176 is the same who appears in a given other story where a Beagle Boy has this number; while a large amount of these stories must have featured this Beagle, any ones where he acts too "evil" compared to his characterization in The Lovebird Jailbird can be chalked up to being a different 176-176.
By that same token, it is impossible to say for sure in which story this particular Beagle debuted; it is even possible that he was among the Beagles seen in the Beagle Boys' debut Terror of the Beagle Boys. His only confirmed appearance is, of course, in the 2003 story The Lovebird Jailbird.