Fans of Supernatural will note that they've seen the character Lucifer from two different universes (alternate reality). In season 5 we are given a glimpse of a slightly different Lucifer. He's more or less the same bitter, betrayed dude, but with one key element changed. The alternate reality Lucifer thinks that Earth is beautiful, and finds the idea of destroying it pretty humorous, something the normal Lucifer would take quite seriously. It's pretty cool, honestly, but alternate universes give us more information on our favorite characters. Had things only gone slightly different and well, we might be looking at a pretty different Lucifer, or Michael or Sam, anyone really. Alternate universes give us a glimpse into the world of what if.