A badger and a dog were made to "fight until the death" in a suspected baiting in Flintshire, the RSPCA has said.
An investigation was triggered when residents of Ffordd yr Ysgol, Flint, found a female badger dead in a pool of blood on Saturday morning.
A dog - a bull breed lurcher cross - was also discovered abandoned in playing fields near Cornist Park County Primary School with serious injuries.
The RSPCA called the alleged baiting a "serious form of premeditated cruelty".
The animal charity received reports of distressed screams in the area at about 1:00 BST.
RSPCA inspector Anthony Joynes said the discovery of the animals was "an incredibly gruesome sight".
He said: "It looks like someone has set this dog onto this badger and then just left them to fight it until the death.
"The badger would have had a horrific death, and she was a female so could well have young somewhere needing her care."
He said the dog, which has since been named Flint, was in a "horrific state" and needed urgent veterinary attention.
He suffered a tear to the ear, a serious injury to his nose, broken teeth and puncture wounds all over his body.
"Animal fighting involving dogs and wildlife is an extremely serious form of premeditated cruelty," Mr Joynes added.
Police Community Support Officer Mike Gray posted on Twitter: "Pretty horrific job this morning..At the aftermath of badger baiting in the #FLINT area overnight".
The RSPCA said it was dedicated to investigating such incidents and bringing culprits before the courts.
It urged anyone with information to get in contact on 0300 123 8018, or to contact North Wales Police on 101.