Symbolism, Imagery, Allegory
The people in Lake Windsor Downs have some majorly weird stuff going on in their neighborhood. If you think lightening, muck fires, disappear koi, termites, mosquitoes, and sinkholes sound a lot like something out of Exodus, you're not the only one. Wayne even remarks, "Y'all are having a regular nine plagues of Egypt over here, aren't you?" (2.14.54).
For the most part, these are natural occurrences. So, what, has Mother Nature gone nuts or something? Maybe she's watched Thor a few too many times?
Nope. All this stuff is the community's own fault. The termites are there because of the way the houses were built; the mosquitoes came because they tried to deal with the muck fire; and the muck fire is there because they cut down all the trees that attracted the lightning. It's just like that poor old lady who swallowed a fly and ends up chowing down on a horse.
So, just as the biblical plagues were sent to the Egyptians because of their own stubborn behavior (their pharaoh's refusal to change their ways), and just as the old lady had to swallow several unappetizing and probably really panicked animals, the people of Lake Windsor Downs brought these natural disasters on themselves.
We guess you could say that the plagues symbolize the way that not fixing something right away the right way can end up coming back to bite you in the rear. Just like Paul's family tried to fix Erik by ignoring his psychotic behavior and ended up just creating a murderous monster.