No, you weren't losing your mind if you were downtown on Sunday, Chicago. This really happened:
According to CBS Chicago, the Fiat jet skis were part of a commercial the car company was shooting on Lake Michigan near Oak Street beach. Per the Drive, She Said blog, they were spotted speeding along both on the lake and on the Chicago River between 11 a.m. and 1:30 p.m. Sunday.
And no, the cars weren't actually cars: they were jet skis souped up to look like cars. As you do.