“Severance” co-executive producer and writer Mohamad El Masri is channeling the Innie/Outie duality for his critically acclaimed directorial debut “Other Other.”

The 25-minute YouTube short film stars Sosie Bacon and Scoot McNairy as a couple who live parallel lives…literally. Myka (Bacon) and Spyro (McNairy) have been dating online for a year before they decide to meet in person for the first time — only to realize that they live in alternate worlds and can’t actually be together. More sci-fi than “The Lake House,” “Other Other” was recently named the Short of the Week, and writer/director El Masri credited his “indie film hustle” for getting the short off the ground.

“I’d worked with Sosie Bacon on a TV series, ‘Here and Now’ on HBO, that lasted for one season. I met Sosie working there as a writer. I sort of kept track of her career as it grew,...