Group P365's Hellhound

"Sweet Celestia, those are hellhounds that the Group P365 has been using. They're all deceased German Shepherds who were revived as zombies. Also, they've got stronger teeth, claws, and even postmortem explosions too. Just becareful with that, okay? That'll be too dangerous. Way more dangerous."

--Su Ji-Hoon, The Fires of War

The Group P365's Hellhounds are the aggressive zombie dogs of the Group P365 that they are deceased German Shepherds who to be revived as zombie form. They are new version of the Hellhounds from Call of Duty

They are revived as zombie form by the Group P365 since they were deceased German Shepherds who being burial in graveyards.

Therefore,they even enter Group P365's mainframe teleporters for randomly spawn throughout the locations (a ball of lightning will usually indicate whenever they spawn) to kill the survivors or the Mane Six or other ponies by attacking with their teeth and claws or by exploding after death.

There are variants of itself : : the flaming Hellhound, the normal Hellhound, the large Hellhound (including Cerberus ) and the self-healing Hellhound who can eat enemy ponies for self-healing