It's a baby Black Rat Snake(Pantherophis obsoletta). Baby Black Rats don't look much like adults, having this bold pattern, which will darken up each time it sheds, until it's a mostly-black adult snake. In Indiana, though, adult Black Rats are known form some rather variable coloration, often showing lots of yellow or reddish coloration between their scales, and this little guy seems to have some yellowish background color which might mean he'll wind up being one of those especially-handsome individuals.

It is a rat snake but not a baby black rat snake. It's a grey rat snake. More common for Indiana. Unlike other Elaphe obsoleta ( black rat snake) whose conspicuous juvenile pattern fades into adulthood, gray rat snakes do not undergo drastic ontogenetic changes in color, or markings. These snakes retain the juvenile pattern of dark elongate dorsal blotches separated by four, or more, pale gray body scales, a light gray crown with dark striping that forms an anteriorly facing spearpoint, and a solid band which covers the eyes and extends rearward to the posterior upper labial scales. The venter is usually off-white or pale gray with darker irregular blotches, and a double row of black spots behind the divided anal plate of the vent. The dorsal scale rows around midbody are usually weakly keeled. Because the gray rat snake shares its range with other members of its species, intergrades of black/gray and yellow/gray rat snakes are not uncommon.

Here is a link that might be useful: Picture of your grey rat snake.