|Powers||Power of over 10,000,000 suns|
|Episodes||11.23 Alpha and Omega|
Sam: We're collecting souls to build a bomb.
Dean: To blow the Darkness to hell.
A soul bomb is a powerful and destructive weapon devised by the witch Rowena. It uses the light and power of hundreds or thousands of human souls, and was believed to be the only thing capable of killing Amara, in hopes that the destroying the Darkness would balance out the Cosmic scales after God was mortally wounded.
It is revealed that with God dying, the scales of the Cosmic Balance are tipping and soon all life in the universe will die as well. The only way to rebalance the scales would be for Amara to die as well. Chuck reveals that the Darkness' one weakness is light, and they would need "10,000 suns set to supernova" to defeat her. However, with Chuck in his deteriorating state, he is in no position to assist. Castiel suggests souls, as each soul has the power of one hundred suns. Rowena concurs, and tells the group that with enough souls she could create a bomb. As Cas and Crowley go to Heaven and Hell to try and acquire souls, Sam and Dean go to Waverly Hills Sanatorium to collect ghosts for the bomb, since spirits are just souls that have not moved on.
After the Winchesters have collected a dozen or so souls for Waverly Hills, Castiel reveals that the angels in Heaven are aware that God is dying and have decided to seal up Heaven and "die with dignity," denying Castiel any souls. Crowley does not fare well either, as he reveals that after Lucifer took over Hell, demons raided Crowley's "stash," leaving him with nothing. Realizing they do not have enough, the reaper Billie enters the Men of Letters Bunker. Having noticed Sam and Dean in Waverly Hills, she offers her services by raiding the Veil of a couple hundred thousand souls. The souls are placed in Rowena's crystal. Since Dean is the only one who could get close enough to Amara, he would have to sacrifice himself as the actual bomb. Rowena performs a ritual that transfers all the souls into Dean, telling him when he gets close to Amara to press his index finger and thumb together, which will activate the bomb.