The Sniffer Dog is an enemy in the Silent Hill franchise. In terms of video games, they only appear in Silent Hill 4: The Room; however, they also appear in one of the expanded universe comics known as Sinner's Reward.
They have dirty, leathery skin which appears to be decaying and, strangely, make snarling sounds which resemble that of a large feline or even a frightened rat rather than a canine. Their gums are prominent and hold large, dagger-like canines.
The male variety has visible eyes, ears and green tinted fur and flesh. Females are missing eyes and ears and are purple-tinted, with longer, sharper claws. The gender and rank of the Sniffer Dog is betrayed by their coloration. Green-tinged Sniffer Dogs, considered to be males, are weaker and less threatening than the purple-tinged variety, considered to be females.