A pet dog has been seriously injured after being thrown from a car said to be travelling at 50mph (80km/h).
Toy poodle Anna bolted on Tuesday while en route to the groomers.
The eight-year-old's owners believe she was then picked up by someone and driven around before being flung through the passenger window on the A472 near the Abercynon roundabout.
Several vehicles were said to have crashed with each other as they tried to avoid the animal.
"My sister had taken Anna to get groomed in the afternoon and she must have been spooked by another dog barking inside the salon - she's very sensitive," said owner Lee Jones, from Mountain Ash, Rhondda Cynon Taf.
"As a result she slipped her lead and ran off, so we looked everywhere and posted on social media in the hope someone had spotted her.
"We heard that a couple of people had tried to grab her for us, but we knew she's far too timid to let anyone get near her," added the 41-year-old.
Mr Jones said he later saw a Facebook post from someone describing seeing his pet being pushed from the passenger window of a white hatchback on the A472 between Nelson and Abercynon.
"We felt sick reading how they'd seen my dog suddenly fly out of the vehicle while it was doing about 50mph.
"The driver behind then had to slam on his brakes to avoid hitting Anna, at which point someone else rear-ended him.
"Other cars also had to swerve at the last minute and Anna went underneath one of them, but we don't think she was actually run over."
Mr Jones said he rushed Anna to a vet for treatment after being reunited.
"She was lucky not to have broken anything or to have any internal bleeding, but she's still unable to use her back legs.
"Apparently there's some swelling on her spinal cord and her nerves are damaged - so she can't stand or walk at all."
Lee said well-wishers had been raising money to pay for Anna's £1,200 medical bills.
"The support we've received has been amazing but I just can't understand why anyone would do something like this to a poor defenceless animal," said Mr Jones.
A statement from South Wales Police said officers had received a call "shortly after 23:00 BST on 24 October following a report of animal cruelty concerning a lost dog".
It added there had been "reports of it having been thrown from a moving car on the A472 between Quakers Yard and Nelson".
It asked any witnesses to contact the force.