WARNING: The following contains spoilers for the WandaVision Finale, "The Series Finale," now streaming on Disney+.

After WandaVision aired its season finale, actor Gabriel Luna joked about how his Marvel role, Ghost Rider, might have caused Agatha's reign of power in Wanda's Westview.

The Agents of S.H.I.E.L.D actor posted on Twitter, "Okay y'all, I'll admit it. Under my mattress may not have been the best hiding place." He ended his post with the tag #TheDarkhold, pretending that Agatha Harkness (Kathryn Hahn) stole the book from underneath him.

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Luna portrayed Robbie Reyes, aka Ghost Rider, in Agents of S.H.I.E.L.D. During his run of the character, Reyes lost possession of The Darkhold -- also known by varying names in Marvel Comics like The Book of Sins or The Book of the Damned -- and tasked himself with bringing the book back to Hell to prevent the Earth Plane from colliding with the Dark Dimension.

In WandaVision Episode 8, fans saw Agatha Harkness in possession of a book that looks extremely similar to the Hell-forged text. Later, in Episode 9, "The Series Finale," Agatha announced to Wanda that the book she consulted to take control of Westview was The Darkhold. After Wanda defeats Agatha using her chaos magic, she takes the book to learn the extent of her powers and what else the magical text can do.

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The Marvel character Roberto "Robbie" Reyes was created by writer Felipe Smith and artist Tradd Moore and debuted in 2014's All-New Ghost Rider #1. His character has since appeared in several Marvel Comic series including 2016's Ghost Rider and 2018's Avengers.

At the time of this writing, there are no active projects starring Robbie Reyes within the MCU's Phase 4. Previously, Luna was set to reprise his Spirit of Vengeance role in a solo series focused on Reyes/Ghost Rider; however, Hulu preemptively canceled the series. At the time of its cancellation, Luna wrote a heartfelt thank you to fans, noting, "I've had the time of my life playing those two guys and I was ready to rock on the new show." He added, "The news is surprising, but I've always known that the nature of this business is that until you're there, on the day, doing the thing it could still go away."

Written by Jac Schaeffer and directed by Matt Shakman, WandaVision stars Elizabeth Olsen as Wanda Maximoff/Scarlet Witch, Paul Bettany as Vision, Randall Park as Agent Jimmy Woo, Kat Dennings as Darcy Lewis, Teyonah Parris as Monica Rambeau and Kathryn Hahn as Agnes. All nine episodes are streaming on Disney+.

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Source: Twitter