Chopan and Mozart are two parts of the same Pokémon. Chopan is the head, and Mozart is the tail.

Almost all Girafarigs do not have sentient tails. At least, not like Chopan. Like most of Radic's Pokémon, Chopan is not like other Girafarigs. The black that's supposed to go halfway up his body is only limited to his tail, and his tail itself has a long, curvy neck and a wide variety of facial features, unlike other Girafarig that have straight tails with a vacant smile.

And then there's Mozart.

In a way, Chopan and Mozart are sort of the same person, in that they developed in the same body. As Chopan grew older, eventually Mozart began to grow and become smarter, more intelligent, and eventually gained enough power to take control of the tail and talk to Chopan through it.

Chopan, already unpopular since his markings and tail looked funny, now became completely outcast because NO Girafarig had a sentient tail. That just did not happen.

Bitter and resentful of his tail, Chopan worked to differentiate himself from it as much as possible. He became rude, short-tempered, and generally a huge jerk. Mozart, in contrast, was friendly and quiet. The two of them argued constantly about everything, and still do to this day. Chopan is one of the few Pokémon out there that can make Mozart lose his temper.

Mozart has enough strength to take control of the body if Chopan is asleep, and that was how he approached Radic one night while he was eating at a campfire. After a short discussion, Mozart decided to join Radic, although he didn't talk to Chopan about this first.

Chopan was NOT pleased to suddenly belong to someone, and this has become a familiar point of contention between them to this day.

Chopan, the head, is frankly a huge jerk. In the tradition of Ruby, Kitsune, or Nova, Chopan does NOT make friends easily. Not particularly clever, he's not good at putdowns or insults, but even the bluntest of insults can anger a Pokémon enough. He doesn't want friends and in fact works fairly hard to avoid them. He doesn't like the rest of his team much either, and he hates Mozart. There are few things that he considers off-limits, and he'll gladly pick a fight with anyone who's willing to get into it with him. He's stubborn and doesn't know when to quit, and the only thing that tends to frighten him, although he'll deny it, are ghost or dark Pokémon.

Mozart, the tail, is a sharp contrast to Chopan in every way. Mozart is friendly and calm, preferring to think things through before acting, and he tries to get along with everyone he sees. Mozart, like Chopan, was ostracized for being a freak, but instead of driving everyone away like Chopan, Mozart is desperate for other people and Pokémon to like and validate him. He also has the added burden of being a tail on top of everything else, and with Chopan and other Girafarig constantly telling him he shouldn't exist, he craves validation from almost anyone who will talk to him like he's his own person.

Mozart, like all Girafarig tails, has a weakness for sweet food, and will sometimes do unwise or stupid things in pursuit of it. He isn't afraid of dark or ghost Pokémon like his other half, but his patience with Chopan tends to run short. While he'll almost never snap at anyone else, he's quick to insult or berate Chopan, who will easily get into it with him in return. They're unpredictable in battle, since Chopan sometimes won't listen to him, or one half will take control from the other.

Despite it all, both Chopan and Mozart care for Radic and are loyal to him, although it doesn't manifest as obedience. As much as Chopan tries to drive everyone away, he's very appreciative that Radic hasn't abandoned him yet. Mozart just loves the fact that Radic actually listens and respects him.

In Johto, Chopan knew Stomp, Psybeam, Crunch, and Confusion.

Chopan and Mozart are in fics where Radic's later Pokémon come into play, mostly Together Forever.