Supernatural's Metatron will return once more in episode 18.

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The king of the jerk angels is currently stewing in heaven's prison, but it looks like Castiel (Misha Collins) will get Dean's (Jensen Ackles) killer a furlough for the second time.

"I'm starting to think picking up this hitchhiker was a bad idea," Collins captioned a photo of himself and Curtis Armstrong (Metatron) in Cas' car.

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Last time the scribe joined up with Team Free Will, Dean nearly ended him, much to Cas' displeasure. The elder Winchester is working on controlling his Mark of Cain rage, but it's doubtful that Dean's angel pal will make that mistake twice.

However, Metatron could still be key to solving the problem of the Mark. He already gave the Winchesters one clue, and it's clear his time penning the Tablets has left him with the entire answer.

While we wait for episode 18 to roll around, fans can catch the return of Cain (Timothy Omundson) in this Tuesday's "The Executioner's Song."

Find out more when Supernatural airs Tuesdays at 9 p.m. ET on The CW. Click the video below to see a preview for "The Execution's Song."