Hamhock

This fiery duck is of a quite aggressive nature and will pick up fights with other Pokémon over anything : a fresh berry, a nice place to rest in the sun, or maybe they just looked at him and he didn't like it. But despite being the one to initiate fights, he constantly gets his ass beaten, which sends him to pout in some corner. However, he has a rather short memory span, and will quickly forget about his bitter defeat, leading him to go back and fight against the same opponent once again. And lose again, of course. This could go forever if it wasn't for the other Pokémon to eventually get tired of roasting the roasted duck, and end up giving up on whatever the duck wanted to get. So I guess he does win his fights, after all ?