Poured A Glass Of Water Last Night From The Tap Left It Under The Light On The Night Stand, Next Morning I Found This Floating In It... What Could It Be?
Answer: If it actually did come out the tap with the water, my guess is some sort of flocculant/coagulant used in tap-water treatment, that somehow made it past the system and was still dissolved/in suspension in the water. Then settled out during the night.
These chemicals are used to attract particle in the water and clump them together for easier removal. Some of those "concoctions" looks similar to this after settling out.
that's just CUM ! 
and to think all sorts of things such as this in our "drinking water"