From the Super Mario Wiki
Shiny-Cone Goombas (known as Shiny Cone Goombas in the PAL version) are a species of Goomba that appears in Paper Mario: Sticker Star. A Shiny-Cone Goomba looks like an ordinary Paper-Cone Goomba, but they gain an added sheen, much like those of shiny stickers. Just like an normal Paper-Cone Goomba, Shiny-Cone Goombas cannot be stomped on unless an Iron Jump sticker is used. Shiny-Cone Goombas attack by lunging at Mario like paper airplanes. Their attack is much faster than that of their non-shiny counterparts. They are very rare enemies since 1 only appeard.