opens with maggots crawling on a dead dog 
(ROOT (VP (VBZ opens) (PP (IN with) (NP (NP (NNS maggots)) (VP (VBG crawling) (PP (IN on) (NP (DT a) (JJ dead) (NN dog))))))))
(ROOT (VP (VBZ ) (PP (IN ) (NP (NP (NNS )) (VP (VBG ) (PP (IN ) (NP (DT ) (JJ ) (NN ))))))))