This is weird, but its lineage makes sense. Roberto Agierre-Sacasa, executive producer of this dark interpretation of the Archie comics world, also was co-author of the screenplay of the 2013 film remake of the Stephen King horror classic Carrie. So when he and his writing and producing cohorts decided to write an episode about the Riverdale kids putting on a high school musical, they naturally decided on doing an amateur production of Broadway’s Carrie: The Musical. After all, Riverdale already has its own fiery redhead: Madelaine Petsch’s Cheryl Blossom. And that music-filled episode premieres tonight.