Wiktionary
horse of a different colour
n. (alternative spelling of horse of a different color English)
Usage examples of "horse of a different colour".
Agility's not in it, when it comes to Palladian, daring alone will carry the day and, though the first storey's graced with a hefty caryatid whose bulbous loincloth and tremendous pects facilitate the first ascent, the Doric column on her head proves a horse of a different colour, I can tell you.
It was, as his Irish lieutenant would say, a horse of a different colour, and Cornelius Killick was not sure he liked the colour.