The famous Greyfriars Bobby on George IV Bridge was seen with a placard tied around its neck mockingly saying "touch my nose, help spread COVID-19" on Saturday night.
The 19th century statue has become subject to a new tradition in recent years which sees people rubbing its muzzle for good luck.
The constant touching has resulted in paint being worn and the local authority having to repair the damage.
But after Bobby was spotted with the sign tourists may feel less inclined to stroke him.
Campaigners have repeatedly demanded visitors stop touching the brass dog's nose due to the damage it has caused.
The National Library of Scotland also called for visitors, and some locals, to stop encouraging the trend.
Staff in the past imagined what Bobby was thinking and wrote a statement 'by him' online saying: “Hello. My name is Greyfriars Bobby
"And I am a statue of a dog.
"Somehow a rumour started that it’s good luck to touch my nose.
"It really isn’t.
"(Not least because I’m a biter!)
"And you will eventually wear it down.
"Please don’t touch it.
In 2018 one mystery campaigner took Bobby's preservation a lot further by cordoning off the Skye terrier statue with hazard tape and a "do not touch" sign.
Greyfriars Bobby was installed in 1872 to commemorate the faithful terrier who kept watch over his owner’s grave for 14 years.
The statue has, in the past, been declared as the Capital’s most-loved object following an overwhelming public vote.