it grabs you in the dark and shakes you vigorously for its duration . 
(ROOT (S (NP (PRP it)) (VP (VP (VBZ grabs) (NP (PRP you)) (PP (IN in) (NP (DT the) (NN dark)))) (CC and) (VP (VBZ shakes) (NP (PRP you)) (ADVP (RB vigorously)) (PP (IN for) (NP (PRP$ its) (NN duration))))) (. .)))
(ROOT (S (NP (PRP )) (VP (VP (VBZ ) (NP (PRP )) (PP (IN ) (NP (DT ) (NN )))) (CC ) (VP (VBZ ) (NP (PRP )) (ADVP (RB )) (PP (IN ) (NP (PRP$ ) (NN ))))) (. )))