whats the meaning of the zombie ?

After he goes to sleep, Paul is wakened by the sounds of his brother running down the hallway and a car pulling away from the house. When he can’t go back to sleep, he starts thinking about a zombie stalking along Interstate 10.

The zombie represents all the bad vibes in the family home in Houston. When they left Houston, they left the zombie. But, because it is a part of the family, it is following them to Tangerine.