Football Outsiders diagrams a very traditional, I-formation set which results in a long run. It's a far cry from the empty backfield sets we used to see:
It is a perfectly ordinary running play. The fullback does a fine job opening up a cutback hole by kicking out the defensive end, then roll blocks the outside linebacker to boot. Those blocks, plus a quick cut and some defensive overpursuit, result in a 39-yard run. Great work, but not the kind of exotic play that I usually diagram here.
The team is the Colts. They are in the I-formation. It is not a goal line or short yardage play; it is first-and-10. That is not a backup defensive tackle playing fullback. It is a fullback playing fullback. With nothing else to lose, the Colts have decided to sometimes use a tactic that the rest of the league has been using for the last 40 years or so.