Spamton and Dess are both characters who start off fine (if not a little troubled) before mysteriously going missing, presumably due to forces beyond them. Dess and Spamton are both not mentioned outside of those close to them, likely because they're viewed as a taboo subject. Throughout the entirety of the game, outside of Pizzapants and the Dreemurr and Holiday families, no one ever mentions Dess. Meanwhile, Asriel is mentioned multiple times by several monsters in Hometown. Spamton is similar; he’s only ever mentioned by Tenna, while the other Darkners in TV World and Cyber City seem to avoid talking about him entirely.

Spamton and Dess’s rooms are also both preserved in the same state they were the day they went missing.

(these are the only times in the game the word "unplugged" is used!) Dess’s room is kept preserved that way due to Carol, who has an obsession with keeping all her loved ones close and static, as shown by her preserving snowflakes against Noelle’s wishes:

Carol's obsession with keeping her loved ones close seems to only really drive them away. Noelle feels detached from her due to her attitude, and grows a desire to break free of control and do what she desires to. A desire which grows much deeper in the weird route. Tenna is similarly shown to care a lot about keeping those he cares about close to him, to a degree that harms them and ultimately pushes them away. He pressures Spamton to write a contract knowing something bad would happen, partly because he wanted them to be together forever, he keeps the Z-rank room and the mailroom preserved even years after Spamton’s disappearance, he traps the fun gang in gacha balls in order to keep them playing his games, and he even puts a sleeping Toriel in a gacha ball in snow. In Chapter 5, it’s revealed Asgore feels guilt about his involvement in Dess’ disappearance and pushes everyone away because of it:

In the same exact chapter, Tenna, who’s similar to Asgore in several ways (hangs on to the past, attempts to be a parental figure to Kris) expresses how guilty he feels about Spamton’s disappearance, and how he pushes others away because he's hung up on it:

(It’s also worth noting that Dess’s disappearance and Spamton’s disappearance are directly linked in the story. The Dreemurr and Holiday families grow apart and stop watching TV when Dess goes missing, which is what prompts Tenna to become afraid of being thrown away and make Spamton sign the contract.)

Noelle also exemplifies how Tenna goes into denial about Spamton’s disappearance. In Chapter 5 of the Weird route, Noelle says this:

She makes sure to specify that Dess left; not disappeared, not went missing, left. even though every previous discussion of Dess led us to believe she went missing due to something outside of her control. This is similar to Tenna claiming that Spamton abandoned him in the sword route ending segment, even though we know Spamton didn’t choose to leave and was instead forced to due to his benefactor.

Noelle also explains that she’s struggled with dissociation since Dess left, which is strikingly similar to Tenna saying that nothing has felt real to him since Spamton left:

This feels even more intentional when considering some of Noelle and Tenna’s other similarities, such as their tendency to hang on to the past, their lack of courage to break free from the systems keeping their lives stale despite a clear desire to do so, how they define themselves by others rather than their own selves, and how they both care about Pipis. Noelle is even sad when you give Tenna away to Mettaton in Chapter 5.