>>534559731
I dont think that the crystal was in the NEO body unless Im misremembering something.
I think he had it to begin with as his dialogue in his shop where he momentarily breaks and asks "... can anyone hear me? Help..." before saying he didnt hear anything but that it sounded like they were talking to YOU.
I think this was Dess talking through Spamton via the shadow crystal.
Remember, it's the shadow crystals that are showing the Darkners that their world and life is a lie.
Jevil saw this as meaning there were no consequences to his actions since nothing matters anymore, and when there are no consequences, you can do anything.
Spamton saw this and was horrified, instilling a new ambition to free himself from his false world.
Gerson was much wiser and likely because he was originally a Lightner, knowing the dark world around him was fake had no impact on him because it doesn't mean the world he left behind was.

Basically Im starting to think there is a very real connection between whatever is in the shelter and the shadow crystals.
Im wondering if in chapter 5, we'll see undyne talk through whoever has the crystal then.