Who is behind generous 'Tips for Jesus'?
A secretive syndicate of super-rich diners have started a trend of leaving lottery-winning tips for bar staff, waiters and waitresses across the US. The lucky recipients are thrilled at the windfall, but is this another sign of the growing chasm between the rich and everyone else in America?
Scribbling the phrase "Tips for Jesus" alongside outrageous gratuities on credit card receipts, the trend - presumably among the super-rich - has set the internet abuzz with speculation over who the ringleader might be.
Pictures of many grinning faces and evidence of their windfalls have been posted on Twitter and Instagram, where #TipsForJesus is not only trending but is unsurprisingly attracting a lot of "likes".
More than $130,000 (£78,027) worth of tips are said to have been left in the six months since the mystery handouts began.
The rich and mysterious tipper or group of tippers have been leaving giant gratuities in a dozen cities across the US and Mexico, but recently the service staff of Los Angeles have been cashing in.
Just last week a waiter at a top Italian restaurant in LA picked up a $6,000 gratuity on a $900 dinner bill, and a fast food server was given a $100 for a $4 milkshake.
Two waitresses at an iconic Sunset Boulevard strip club, Jumbo's Clown Room, shared $2,000 in tips on a $272 bill.
But the undercover benefactors have also been operating in New York, Arizona, San Francisco and Palo Alto, and it's there where many people think the secret to the lavish spending lies - a Silicon Valley billionaire.
Some insider magazines have gone as far as to name former PayPal vice-president Jack Selby as the mystery money man, but he's keeping quiet and those responsible remain out of the public eye.
And apparently "Tips for Jesus" has nothing to do with religion.
Widening wealth gap
The ringleader asked to keep his anonymity in exchange for an interview with the San Francisco Magazine.
"The movement we started is intended to be agnostic," he is quoted as saying, suggesting he can't remember exactly how it all began, other than it being last September after a college football game in Michigan.
A $3,000 tip on an $87.98 tab, with a photograph posted to Instagram, and ever since then a flurry of local media interest has followed news of the latest big gratuity.
The ringleader has "been fortunate" in life, the magazine says, adding he and his friends had been big tippers for years - just not this big.
Rubber stamps have even been made, and there's a possibility copy-cat tipping is going on - something welcomed by those lucky enough to share in the peculiar redistribution of wealth.
Tipping is part of culture in the US, where there are traditionally low wages for serving staff, but this is a curious form of luck-based philanthropy.
It's a reminder, perhaps, of the widening wealth gap between the super-rich and the rest across America.