I can't find much on this mythical creature. The internet is, at least on this score, lacking in valuable information. However, the creature is fascinating.
Meet Balachko, a three headed giant from Slavic (Serbian to be more precise I believe) mythology. This giant could breathe fire from one head and ice from another. Presumably the other head did all the thinking, planning, and talking.
From what I can gather the giant was more a nuisance than a threat until it either successfully kidnapped or tried to kidnap a princess before/during/after a wedding. It was then slain by a hero.