TIL Discarding a Shifter Zerus turned into Clutchmother Zavas gives you back a buffed Shifter Zerus, and not a "real" Clutchmother.
https://imgur.com/a/Ultsm
I had the chance to get both Clutchmother and a Darkshire Librarian from 2 Shifters today. While it discarded the Clutchmother, the card coming back into my hand was a Shifter Zerus shifted into Clutchmother.
Thus the next turn it changed again, but kept the buff (like probably any handbuff you'd apply to Shifter).