Graffiti was discovered early Monday morning on the north side of the Shawnee High School Performing Arts and Athletic Center.
According to SPS Public Information Officer Cherity Pennington, the vandalism stretches across the wall and maintenance workers have already begun the clean up process.
"This will require paint and sand blasting...," Pennington said. "It could be very expensive for whoever did it."
Pennington said administration is looking over security camera footage and believe they're close to finding the culprit or culprits.
The vandalism depicts various phrases and pictures from "Alice in Wonderland" and seems to be a proposal to the high school's prom.
"This is not going to be easy to clean up," Pennington said.
In the state of Oklahoma vandalism damage costing $1,000 or more is a felony.
Pennington said there have been two unrelated acts of vandalism at Will Rogers and Sequoyah Elementary Schools.
The graffiti was not as severe and both were cleaned up the same day they were discovered.
Check back for updates.