Mari's room, after dinner:
"You were right."
Mari says nothing, waits.
"The purple foam things don't burn; I saw one of them at the bend at the end of the corridor — I think the girl it had been chasing got away — so tried to burn it. It didn't even notice.
"That means it is immaterial, so throwing things at it won't work either."
"Could it just be fireproof?"
Ellen shook her head.
"The big snake I killed was fireproof. It still noticed the first time I tried to burn it.
"Apa never taught me what to do about immaterial mals and he isn't here to ask. We have to find something."
Mari got up from the bed, spoke firmly to the void wall of her room:
"I want a book about immaterial mals."
The void hesitated briefly before a book fell out. Ellen picked it up, started to read.
Mari spoke to the void again:
"I want the most recent article on immaterial mals in the Journal of Maleficaria Studies."
A longer delay before the copy appeared. Mari took it, checked the table of contents, started reading. Stopped.
"Tomorrow at breakfast, talk to Sandor. I'll talk to Marcy. We don't have to do it all ourselves."
If Ellen can get Sandor interested enough to talk to her ...