Human Dog (人間DOG) and Human Dog Baby (人間DOG Baby) are prototype versions of Dog.com. According to a PC Watch article, Dog.com is more advanced and smaller than Human Dog.
TOMY first decided to make Dog.com gold, but later changed it to blue. This may have been due to visitors of the Tokyo Toy Fair questioning why the Human Dog is gold, and stating that blue would have been a better color choice. "Human Dog" was also Dog.com's original name before it was changed.
Three prototypes for Human Dog, plus a smaller version of it, are known to exist. I had a bit of trouble trying to describe this dog's appearance, but I tried.
Human Dog's eyes are white, its head, body, and legs are gold, and its nose is a dark shade of red. Its nose doesn't look like it's supposed to light up, like Dog.com's nose which is translucent. A large portion of the chest has a bean shape that is silver, and near the end of the left side of each leg is a silver circle. Human Dog's feet and tail are silver, but the tip of its tail looks like a golden egg. The middle portion of the dog is thinner than the upper and lower portion, and is silver. Before and after the middle part of the dog, the dog's design has what look like two large gold rings with circular bumps. The bolt/screw, visible in the photo, for this prototype's jaw, has a gold, circular cap. Its face has a raised, circular bump near its snout on one side, and two raised circular bumps on its ears (there's only one photo of this prototype showing one side of it, but I'd guess these bumps appear on the other side of the dog, too). Unlike Dog.com, this and the other Human Dog prototypes known to exist have each of their eyes embedded in small, gold arches which stick out, and there is an empty gap between both their eyes. Dog.com's eyes are similar, however, there is no empty gap between their eyes.
This prototype has the same look as prototype 1, but with some differences. The bolt/screw which hinges the jaw has a silver, circular cap, and the head is attached to the body differently. For prototype 1, there is a circular, gold, plate, to which the head is attached. For prototype 2, the head is attached to the body by what appears to be a rectangular white/silver piece for its neck. I don't know if it moves its neck the same way Dog.com does, or if the neck is supposed to be something like a slot that can allow the head to bend. I haven't seen video footage of Human Dog. Prototype 2 is also missing a circular bump near its nose, and this prototype's body is more blocky and less round, in contrast to prototype 1. The silver patch on its chest is almost the same shape as the chest area.
Only 2 units of this prototype are known to exist. The two prototypes and Human Dog Baby were shown at the 2000 Tokyo Toy Fair.
This prototype is a lot like prototype 2, except, its chest has a few small holes. It was on display at ROBODEX2000.
Human Dog Baby looks a lot like a miniature version of prototype 2. It has a small, circular bump near its nose, like prototype 1. Only 1 unit is known to exist.
Human Dog is capable of speaking actual words like a human, and in Kansai dialect. An ASCII article states Human Dog speaks in an old man's voice, and has a vocabulary of approximately 20,000 recorded words. Human Dog was created to communicate with its owner, and to use more of its vocabulary the more you and Human Dog get along. Unlike Dog.com, Human Dog expresses itself by lighting up its eyes. Human Dog Baby can't talk as much as its fully-grown version, but it can communicate with its older version.
Human Dog has 17 motors and sensors such as a light sensor, sound sensor, contact sensor, touch sensor, and tilt sensor.
A box with photos of Human Dog's head, taken from different angles, exists. However, the box also says "Dog.com" on it, and appears to have 2D art of a Dog.com as well.