Maybe he needs to go through this bullshit every time he respawns, and because his assimilation rate is getting lower he's able to remember it, or be conscious of it while it's happening, or whatever. Or maybe the author just wanted to draw a shitload of skelleys.
huh? seems like his caster is trying to make the ultimate skeleton by having them do a battle royale amongst themselves? maybe the caster makes all skeletons go through this "dream"
Who knows tbh, I give up at this point. Hope the reveal comes soon.