To the surprise of her owners the rabbit, known as Fluff, grew the unusual pattern just before Christmas.
The pet’s head now looks like a hot crossed bun.
Kate Hazel, 51, said the holy symbol had the whole family speculating what it meant.
She said: “We’ve been wondering if it’s the second coming of Jesus…in rabbit form…in our garden in a rabbit hutch.
“My daughter Rosa said, ‘Mum, Fluff’s turning into the Baby Jesus’.”
“I had a look and it was really pronounced. It didn’t come gradually, just suddenly, one day, she had a cross in the middle of her forehead.
“So we were then calling Fluff the Baby Jesus because she’d come in time for Christmas.
However, it has also been suggested the rabbit’s forehead now looks like the traditional black and white cross found on the flag of Cornwall, known as the St Kiran flag after the region’s patron saint.
Ms Hazel added: ”Someone else saw it and said, ‘It looks just like St Piran’s cross.’
“So, she’s either a reincarnation of St Piran, or the Baby Jesus, or both.
“I’m not religious, but some people think they are a sign of something happening.
“But, you know, she’s just a Cornish rabbit with a cross in the middle of her forehead.”
The family are unsure what caused the cross to appear or whether it is here to stay.
“Maybe it’s her new fur coming through, or her old fur, whichever way you look at it. So, she might shed it or it might stay there,” Ms Hazel said.
“She might grow something else. She might have a crop circle on her bottom next week.”