Ghosts or Camera Exposure

Received from the SPI FB inbox from Ian Selvaraj

Hello there,

I was hoping someone could help me figure out what this was. I took aphoto of the first floor corridor of my block and only afterwards realised that there was a lot altar right in the middle of the shot. After I had the film developed, I noticed what looked like a smudge or an overexposed portion of one of the pictures.

I scanned it and was shocked to see this weird, almost like a ball of light, floating through my image, right below where the lit altar was. I know it couldn't have been a light leak as none of the other images have any problems and the film I was using allowed me a decent shutter speed to prevent blurring.

The first photo is in its purest, true to the film negative scan. The second one I edited to increase the contrast and lessen the highlights a little. I Would love to hear from anyone if possible on what this could be.

Best regards,
Ian