#cat 3

Drawing my menace of a cat: Gizmo

Images of the guy himself under the cut

Oh no worries! So unfortunately I was not present live during s15 airing, but from what I have gathered, why lamp/lampgate has to do with that scene in 15x10 The Heroes' Journey, when Dean goes to Garth to get his cavities filled. He hallucinates/has this dream sequence where he tap dances to "Let's Misbehave" by Cole Porter which apparently has a ton of LGBTQ+ lore attached to it (via @deanwasalwaysbi). Definitely read through that post which goes into a lot more detail.

The long and short of it is that the lamp is theorized to be a stand-in for Cas especially since at the very end of that episode he is looking at Garth and Bess dancing in their living room and is like "I always thought I'd be good at dancing" or something similar.

From there, my understanding is that fandom did lamp=light and looking back on various episodes, there are lighting shifts whenever Cas is mentioned in the context of Dean. Off the top of my head, an example is at the end of 13x05 Advanced Thanatology when Dean gets a call from Cas saying he's alive and his face both figuratively and literally lights up.

There are also often instances of Cas standing under lamp posts which are supposed to symbolize a halo since we don't see actual halos in the spnverse.

Additionally in Dean's room in the bunker, there is furniture doubling at times, can't quite remember the specifics right now, but there are times when there are 2 table lamps/end tables and times where there are not. I believe in the finale everything is doubled and in comparison the absence of Cas is LOUD especially when taken with the insane number of empty beer and liquor bottles littering the place. (Don't take my word for this though because I've seen the finale exactly once.)