"Ngexisaurus" is the informal name given to an as yet undescribed genus of dinosaur from the Middle Jurassic. It was a coelurosaur which lived in what is now China. The type species, "Ngexisaurus dapukaensis", was coined by Zhao in 1983.
References
Zhao, X. (1983). "Phylogeny and evolutionary stages of Dinosauria." Acta Palaeontologica Polonica 28(1-2); 295-306.