be (really) something
To be particularly noteworthy, remarkable, interesting, special, or impressive. Wow, this new car of yours is really something! A: "I hope we get a chance to meet the band after the concert." B: "Yeah, now that would be really something!"
oh really
An interjection of interest, surprise, or irritation, usually said in response to a comment from another person. Oh really? How do you know my mom? Oh really? Well, if you don't need me telling you what to do, then I guess you don't need me cooking for you either!