a one-trick pony

a one-trick pony

A person, group, or thing that is known for or limited to only one unique or noteworthy skill, talent, ability, quality, area of success, etc. The app developers took the world by storm with an incredibly addictive game for smartphones, but they've really been seen as just a one-trick pony ever since that breakthrough success. As most readers suspected, the famed fantasy writer turned out to be a bit of a one-trick pony, genre-wise, with his debut novel in literary fiction being universally panned by critics.See also: pony

one-trick pony (or horse)

someone or something specializing in only one area, having only one talent, or of limited ability. chiefly US 2005 DVD Verdict Joan Collins…may be a one-trick pony (she's been playing nothing but variations on her Alexis Carrington for the past twenty years), but what a trick it is. See also: pony