As many as 20 artfully carved faces, miniature versions of the Easter Island sculptures, have been deposited in sleepy villages across northern England in recent weeks, leaving the recipients intrigued and confused.
Each of the stone heads, some measuring up to 45 cm (18 inches) high, is slightly different, but all of them have the same riddle attached, written on a thin blue card.
"Twinkle twinkle like a star, does love blaze less from afar?" it reads, with the word "paradox" written around the points of a star.
"It appeared last Monday in the early hours of the morning," said Fiona Gould, the owner of the Forresters Arms Hotel in the village of Kilburn, North Yorkshire.
"I love it. We've nicknamed it Forest Lump. We've put him on the end of the bar and he gets a pat on the head before everyone goes to the races."
Valerie Hoyes, who runs the post office in the village of Braithwell, about 40 miles south of Kilburn, discovered hers back in August, but thought nothing of it. She didn't tell anyone until others came forward...
— Red Panda, Totally Stoned, Light Reading