Tonight on "Supernatural," the Winchester brothers went on a road trip to fight demons and monsters, and the fun episode was all seen from the point of view of their beloved car, the Impala. At one point in the episode, Sam (Jared Padalecki) had a vision of the younger version of their dad. Instead of having Jeffrey Dean Morgan reprise the role, the show's production had occasional guest star Matt Cohen play the part, which was a huge surprise for the cast.

In an interview with TVLine, Padalecki revealed how production was able to keep Cohen's return a secret.

"On the call sheet, they didn't want to put Matt Cohen, so they put Leonard Cohen in case anybody picked it up," said the actor.

Padalecki said that it was "a neat thing" to have Cohen play the role instead of Morgan since it put Sam in an awkward position.

"It wasn't the dad that he knew, so it had Sam really unaware," explained Padalecki.

The episode also saw the debut of new creatures that the brothers dubbed the ghoulpires, which means a being that is half ghoul, and half vampire. The ghoulpires' leader formed an army to go against The Darkness, and Jensen Ackles said that the leader's actions "goes back to those unique alliances that are taking shape." But while the ghoulpires will also be dealing with The Darkness, Ackles said that the fight against the Big Bad will mostly focus on Sam, Dean, and the people around them like Castiel, Crowley and Rowena.

And while the Winchesters barely know what they are up against, Ackles said that in upcoming episodes, more characters will be coming and they will have some information about The Darkness.

"In around episode 9 and 10, we'll have some cool characters that have some interesting things to say about The Darkness," he said.

Next week, in the episode titled "Thin Lizzie," the brothers will investigate a series of murders at a bed and breakfast that used to be Lizzie Borden's home. When a man claims that he saw a little girl near the place around the time of the murders, Sam and Dean suspect that Amara is behind the killings.

"Supernatural" airs on Wednesdays at 9/8c on The CW.