C83 A demon is a foot high a dao is a foot high

I was about to go outside to grab some soil when Gu Lvhan stopped me.

"Earth Elemental Magic is useless against him."

"Then what should I do?" I asked anxiously.

"If I just stick this spell on him, he'll reveal his true form."

It sounds very simple, but the other party isn't an idiot. Furthermore, they aren't wood people