In this episode, the Winchesters have decided it’s time to kick Lucifer out of Castiel’s vessel and they enlist Crowley’s help.
Castiel: Wait. That was Dean I saw a minute ago, wasn’t it?
Castiel: And he wants me to expel Lucifer?
Castiel: Well… he may have a more objective view of the situation. Maybe I should.
Crowley: So, let’s do it now before it’s too late.
Lucifer: It already is. Really, Crowley? You want to put me back in the Cage? Well, I’m not going anywhere, and neither are you.
Lucifer: You second-rate bean counter.
Castiel: Guys, you’re gonna break something.
Lucifer: You wanted my throne. You plotted to replace me!
Lucifer: As if ambition and posturing were the same as majesty!
Lucifer: Everyone in hell despises you and sees you for exactly what you are — nothing.
Crowley: Useless. Lucifer’s hold on him is too strong.
Well, that didn’t go too well! Castiel evicts Lucifer from his vessel before the end of season 11, but Lucifer tries a few other meat suits before being returned to Nick in the middle of season 12.