A $1000 reward is being offered to catch the person responsible for burning Jack the dog, which had to be put down after the attack in Western Australia.
RSPCA WA has also revealed four other "horrendous" cases of animal cruelty in the past two days.
The other incidents include a puppy bashing, an emaciated foal that had to be euthanised, a neglected cat that was put down due to large tumours and a neglected dog with a severe skin condition.
Neighbours found Jack in Geraldton on Tuesday morning with extensive burns to his belly, face, legs and paws, and rushed him to a vet clinic.
But infection started to set in the next day and Jack's organs began to shut down, so it was decided to end his suffering.
RSPCA WA chief inspector Amanda Swift urged anyone with information to contact the Cruelty Hotline and said a $1000 reward was available for information that led to the successful prosecution of the perpetrator.
"Somebody in Geraldton knows who did this to Jack. I'm asking them to do the right thing and come forward," she said.
"This innocent dog suffered immensely and lost his life because of what this person did to him."
In a separate incident, a seven-month-old puppy is in surgery following reports of a bashing by the animal's owner in Perth's south.
An emaciated foal was also left to die in a paddock in Bunbury and had to be euthanised.
A cat in Mandurah was euthanised after it was found suffering from large tumours on its head and body, some of which were infested with maggots, seeping pus and bleeding.
In Perth's north-east, a dog was found suffering from severe mange and the animal is undergoing treatment at the RSPCA WA Animal Care Centre, where it is expected to make a slow but full recovery.
The RSPCA is gathering evidence to prosecute each case.