I was on a server with my friend (hosted by him), when I noticed that when I went from spectator mode to creative mode while not holding anything that my hand wasn't there in 1st person view. I looked into my inventory, and my entire player model was gone. When doing things e.g. switching item slot in hotbar or flying around a bit, the player model goes back to normal. The glitch proves to be consistent, too.

How to do the glitch:
Step 1: When in creative, go into spectator mode.
Step 2: Go back into creative mode.