It is a Krag bayonet, technically the Model of 1892. After WWI, the Krag was long out of service, and the rifles were sold off for as little as $2.50 and the bayonets for $.50, with scabbard. Many rifles and bayonets were bought for high school and college color guards, drill teams, and the like, and quite a few were fancied up with chrome or nickel plating (usually chrome - nickel was more costly).
That is one such bayonet. Once there was probably a Krag rifle with its metal parts plated to match, a really snazzy outfit any color guard member would be proud of.