Parasite Dog

Parasite Dog is the first parasite Shinichi and Migi encounter. This is the only known parasite to have an animal as its host.

Appearance
In the anime, he has the appearance of a Corgi with brown, black, and white fur. He has short legs and is wearing a sweater that says "I love animals". Around his neck is a red collar with the leash still attached, though the end of it is bitten or torn off. In the manga, the dog is much larger and has a more wild and dirty look.

Personality
Like many other parasites, he was distrustful of Shinichi and Migi and was quick to try and kill them. Migi stated that due to where he matured, he was less intelligent than a human parasite would be and left himself defenseless while battling.

Plot
In the manga, the host is first seen late one night barking at a parasite, while it was still in its worm-like state.

Later, this parasite is then seen cannibalizing another dog, when he is approached by Shinichi and Migi. He makes note of Migi's position in his host and says they both must be dissatisfied as failures. He begins emanating bloodlust, causing Migi tell Shinichi to flee. To follow them, he then morphs his head into a pair of wings and takes flight. After the dog catches up, Migi quickly engages him in combat. Though he initially dodges multiple attacks, Migi eventually strikes and is able to remove his heart. This causes the parasite to fall to the ground, shrivel up, and die.

Abilities & Powers
Being a parasite, he can shapeshift from the head up and and harden his cells for offensive or defensive purposes, as well as detect other parasite signals and automatically emit his own. He can also maximize the host body's physical potential and disregard pain. He is the only parasite seen to form wings and give himself the ability of flight.

Weaknesses
Like all parasites, he requires a host body with functioning organs to survive, and would die if he were separated from the body or it was destroyed. Fire can cause his parasite cells to "freak out", making him lose control. He is also susceptible to poisons or caustic chemicals, which would either kill parasite cells on contact or make his host body fail.

As an animal parasite, he has less access to resources than a human parasite would. Migi also states that his wings created a blind spot and decreased his ability to see, which allowed Migi to kill him.