The car, which has been parked in Dundas St for about a week, started out with two road cones placed on the roof late last week.
Megan Bowker, who lives nearby, said two quickly became seven and then a couple of cones were hung off the wing mirrors.
A sign was sourced and then the car was almost completely covered.
She said it was almost as if there was a hive-mind effect under way, as all those who who added cones were unknown to one another.
It was "100%" a joint effort by a bunch of strangers.
"Just your usual student antics."
Ms Bowker had noticed the car had been parked in the same spot for quite a while.
"So I’m not sure if it’s been left or it’s someone local — but it’s still here now."
As contractors came back to the street yesterday to continue work, they removed the cones and put them back to where they were being used around roadworks in the area, Ms Bowker said.
"Maybe I should put another cone on and see if it happens again."
The owner of the little red car, Kyla Wilson, said she had "no idea" how the cones got there as she was out of town and only found out about the prank when she saw it on social media.
"I don’t mind; it was funny."
She had parked the car on the street as her flat had no driveway and she was off visiting family outside of the city.
"I thought it was funny.
"I had no idea about it, but I wasn’t worried."
