Herds a weird one for ewe: sheep across the UK are mysteriously appearing emblazoned with a smiley face on their wool. It was first spotted among a herd of about twenty sheep in Leicestershire and, since then, there has been sightings of the mysterious markings at a further five fields - some more than 500 miles away from each other.

Creepy Sheep sightings, as they've been dubbed, are being posted to Twitter with more and more every day, it seems. Pranksters are the most likely source for the bizarre markings, but apparently some are convinced that aliens are behind the pranks.

Ros Turner, a farmer whose sheep were among those marked, was quoted by The Sun as saying: "It's like crop circles - on sheep."

Yes, Ros. It most certainly is.