By The Nation
The seven-year-old male dog's owner and neighbours took the injured animal to the hospital when it was found at 8.30am.
The attacker apparently broke off the top of the home-made harpoon, leaving five forks stuck in the dog's body.
Somchai Thuasue, 36, the dog's owner, said he let the animal roam free in front of his house in Moo 12 village of Tambon Khukot because it was not fierce.
Somchai said his dog would bark at strangers and it might have barked at someone catching fish near the house late on Wednesday night, prompting the attack.
Somchai said the dog probably went into hiding after the attack and came out to seek his help in the morning.