On the fifth season finale of Supernatural, Castiel exploded and Lucifer broke Bobby's neck. Ouch!
Soon, however, both these recurring characters were resurrected because, let's face it, this is Supernatural after all.
Castiel returned to heaven as "the new sheriff in town." Moreover, when Dean and Bobby said farewell, the narrative told us this would be "the last [they] would see of each other for a very long time."
We can confirm that time will come in season six: Zap2It reports that both Misha Collins and Jim Beaver will appear again in the fall. Bobby will remain by the sides of Dean and Sam, while Castiel will put his regained angel powers to good use.
For more sixth season spoilers and teases, check out this CW press release.