A big reveal on the last episode?
I don't see people talking about this..
Tabitah explains that when the man who feared the dolls died, his nightmares became real. And when she remembers the totems are supposed to protect you from the dolls and able to harm them, the last doll on fire decides to leave after.
As if the totems weren't working until someone thought they were supposed to protect them. And things do seem like they work based on beliefs, so maybe Boyd also thought the talisman would protect him and its the only reason it works?
From there almost everyone feels that way, so when randall tries to use it against the monsters they tell him "Thats not how it works", because there are more people who thinks about them differently.
Edit: Thanks for the comments!
I rewatched some episodes, i think the dog is supposed to represent a belief from native americans, maybe those with strong beliefs can create helpful entities, or even neutral ones like the hollow trees. Fatima seems to be doing something similar with the golem she is trying to make.
If that's the case then maybe once someone creates something and pours their beliefs on it, it just works?
We'll have to wait to see what the scarecrows are supposed to do, i find it weird that she realized they're a weapon, because if they had a way to kill them they should be gone already?