it's a four point perspective so ofcourse it's warped >.<
well four point perspective isn't covered in manga... (well maybe some put it but it's really difficult to use)
i saw some of four point perspective in scenes in anime that are looking from bottom to top.. to make it look big or something.. and there are others but don't know when and where it should be used.
well i for one won't put something i don't know how to draw.. >.< (it's not really that hard to research anyway.. I've seen pictures in google)