Interesting take on mold. Usually, a yukkuri is usually portrayed able to digest anything, thus the stories where they end up as garbage disposal. So moldy food doesn't really affect them, and most mold stories are due to their squalid living conditions (mold does grow everywhere) and the humidity. Perhaps this deibu is a sloppy eater, getting crumbs (and thus, mold) everywhere, giving the mold time to transfer over and "infect" her skin.
Agree on that. Usually it's more convenient for authors to make the yukkuri able to eat anything. They might even (barely) survive poisonous or spicy food as long as the dosage is not too much. That way they can humiliate the yukkuri by turning them into garbage disposal.
And then another two days (yu-mould has consumed her whole body. the skin starts to rot and falls off)
"Yu... mister paste... please... stop..."
"Mister... feet... please... move..."
"Deibu... don't want... to.. die..."
"Yu... yu... yu... yu... yu... yu..."
"Want to take it easy more...!!"Another two days after (the paste with higher water contents starts to rot)
"Why did... Deibu get yu-mould!!?"
"Mister Paste, don't go out on your own from Reimu's insides!"
"Stop! Please stop! Right now is fine!"
"Why don't you stop!?
Deibu will die like this!!!"
"Yugaaaa!
Yu-diarhea is not easy!!!"