Its not a shadow, its an obstruction that looks exactly like the triangular building in the image below in this thread. Shanghai is a city of 55 million people, in China, in a city where there are 100 million cell phones all with cameras. If this was a "real" phenomena we would have shitty social media tags, multiple zooms, multiple angles and thousands of eye witness reports. It is hard to get a sense of scale on shitty hand held anything recording, but the object looks bigger, say the size of the top of a massive sky scraper taken from not street level through a marine layer. In fact, it looks like Tomorrow Square, a thousand foot tall building that is in about the right spot relative to the stills I see of Shanghai in the day time. https://en.wikipedia.org/wiki/Tomorrow_Square Its a fucking building shot by tourists through a marine layer in about the right part of the city to see a 1000 foot tall building peek out through patchy clouds. Come on guys, this one is not even fucking trying.
Couple things: 1) The moon is an area source of light, not a point source, and as such casts umbra/penumbra shadows. If this were a dark object backlit by the moon, the shadow on the clouds would not be crisp like it is. 2) I have never been to Shanghai but it looks like it tends towards a low marine layer. Uplighting from below is going to be brighter just because of the distance fall-off. If this were Denver? Yeah I could see the argument but I mean