Hannah Blandford was with her pet in the village of Tremeirchion when she came across the spectacle which has been dubbed an 'alien pod'.
The 33-year-old who works as a teacher told The Sun: 'I couldn't believe how perfectly dome shaped it was, it looked amazing, so I had to take a photo. I'd never seen anything like it before, it was really quite special.
'I watched it for about 10 minutes and then the dome started to flatten and it looked like very thick low lying cloud. It spread out across 12 fields and covered a huge area.'
Forecasters think the fog dome was caused by heat rising up from the ground. Read More