Before Supernatural claimed the record of The CW’s longest running series, the previous holder was the Superman prequel series Smallville, which also debuted on The WB and ran for 10 seasons from 2001-2011.
So they find out that Tom Welling from Smallville is next and have to save him.
They had an episode where they really wanted to do a Superman curse that was about every actor who plays Superman ends up getting killed.
“There was a lot of really cool ideas that some of the writers had.