Gozarutchi sadly comes from bad care. It's sad because I think he's really cool. But yeah, just neglect your Tama a lot but be careful not to kill it. In V4, I think Gozarutchi can only be a male. Good luck.
On V4 you need a universal teen that's a boy. Like, Obotchi or the tooth character (can't remember it's name). Then, neglect it, don't give it many skill points, or take good care of it but I think which universal adult you get is random. There's Pyonchitchi, Gozarutchi, and another character....
well, in my V1 (yes, i have the original!) you have to take really bad care of it. You need an onionchi (eh...don't know how 2 spell that) and a young mameichi i think