Ranma ½ - Season 1

It's not easy being teenage martial artist Ranma Saotome, but it's even worse when your martial-artist father Genma takes you from home at an early age to go on a decade-long training mission. He doesn't speak a word of Chinese, and yet he insists upon bringing you to the cursed training ground known as Jusenkyo, where falling into one of the many springs there instantly turns you into whoever-or whatever-drowned there last. And then, the two of you have this little accident...
From now on, a splash of cold water will turn your father into a giant panda, while you...well, you turn into a red-haired (and problematically well-built) female version of yourself. Hot water will reverse the effect, but only until the next time. What's a half-guy, half-girl to do? (official distributor synopsis)