Unidentified color changing object in sky Yesterday, I was just star gazing and I noticed some star-like object moving with a high speed somewhere near the Orion's Belt and exhibiting all the seven colors i.e VIBGYOR and after a few moments, it disappeared. Any plausible explanations for this observation?
Probably a satellite flare

It sounds like a satellite flare. 

Coming, showing up clearly for a few moments, moving, then going away, are characteristic of a satellite flare, like Iridium flashes. 

Check Heavens Above or any other similar site to see if any predicted flares match with your location and time. 

The changing colours can be explained with "Twinkling".