This is the moment when Jacob realizes, if only for a second, that the stories his grandfather told him were true. Or at least partially true: Monsters exist.

Grandpa is either senile in thinking monsters are after him, or brave for wanting to stand up and fight them. At this point, it's difficult to tell which.

It's a good thing Jacob has brave friends, too. Well, owning a gun is either "brave" or just kind of a Florida thing. We're not sure which.