Scarecrow is Marie's interpretation of Vanir.
While adapting a musical based on the Supernatural books, Marie rewrote Vanir into a scarecrow who was based on a local legend she heard of as a kid, and was afraid of. The scarecrow from the legend was described as "old and creepy" and it existed on an abandoned farm outside of town. Kids often said that if this scarecrow caught you, it would take you away.
When the deity Calliope discovered Marie's musical, she decided to kidnap anyone who tried to interfere with its production. She did this by manifesting the Scarecrow. The first of the Scarecrow's victims was Ms. Chandler, whose subsequent disappearance drew in the attention of Sam and Dean Winchester.
Marie had an argument with fellow student Maggie over the script, and viewing Maggie as a danger to the musical's production, the Scarecrow was sent to kidnap her as well. Marie witnessed the incident and was visibly shaken by it. When she reported her findings to Sam and Dean, they initially suspected a Tulpa was at work, driving them to burn Marie's scarecrow prop.
The burning did not solve the issue, as Sam found out that the culprit was actually Calliope.
Marie was encouraged to continue working on the musical while Sam and Dean hunt for the Scarecrow. Unfortunately, Sam got kidnapped as well and taken to the school's basement, where Ms. Chandler and Maggie were. When Calliope revealed herself to the three, they worked together to defeat Calliope while Dean fought off the Scarecrow, who had come for Marie.
Sam managed to stab Calliope with a stake at the same time Marie stabbed the Scarecrow. Both disperse in purple goo. Since the Scarecrow was on the stage, the audience got covered in the Scarecrow's "remains".
- John DeSantis is uncredited in the episode.
- The Scarecrow was a reinterpretation of Vanir, who appeared in the episode "Scarecrow".