Rex was an Army dog serving in WWII who underwent experiments to make him a canine super soldier, which boosted his intelligence. Following the war Rex went home with his handler and quickly became his son Danny's loyal companion, though the US government did still borrow him from time to time. Many years later he drank from the fountain of youth alongside his longtime friend Detective Chimp granting him a younger body and immortality.
The canine hero has joined or allied himself with several teams and organizations over the years, most consistently the Bureau of Amplified Animals, an American government branch that hires animals with uplifted intelligence regardless of whether their employees gained their brainpower by experiment or magical mishap. He also joined Superboy and the Ravers, a team that never had an official name, and allied himself with Shadowpact.
Rex the Wonder Dog appears in:Notable Comic Books
- Adventures of Rex the Wonder Dog Vol 1 (1952 - 1959)
- DC Comics Presents Vol 1, #35 "Whatever Happened to Rex the Wonder Dog?" (1981)
- Superboy and the Ravers (1996 - 1998)
- Shadowpact (2006 - 2008)
- Action Pet: Rex is a pet that will get up and leave the house and his master in the middle of the night if he thinks someone nearby needs saving.
- The Ageless: After drinking from the fountain of youth Rex regained his youth and ceased aging.
- Canine Companion: Rex is a loyal dog, at first to his master who was killed in WWII, then to Lt. Dennis during the war and to Lt. Dennis 's youngest son Danny when the war ended. Many years later he chose to stick by and protect a teenager named Hero when the boy proved a Weirdness Magnet.
- Cool Pet: He's a dog that can dodge bullets, read English, and live for at least 40 years before he drank from the fountain of youth avoiding the sadness most dog owners face when their dog kicks the can in a much shorter timeframe.
- Evil-Detecting Dog: Rex can sense and smell evil intent, which usually gives him advance warning of anyone trying to attack him or those around him.
- Heroic Dog: This dog isn't just a good people loving dog, he's an actual superhero in his own right.
- The Nose Knows: Rex has a very strong sense of smell, and can tell if someone's evil or lying with a sniff.
- Super Serum: While it was given that Rex had been made an Uplifted Animal somehow while in the army a later more thorough telling of his origin made it rather suspiciously identical to Captain America's.
- Super Soldier: An Army dog that can detect mines, rescue POWs, read English, shake off getting hit by a car, understand English and Japanese, and dodge bullets due to an experiment and training.
- Uplifted Animal: Rex was presumably a normal puppy before the experiments which led to his near human intelligence. Even if he can't talk since a dog's mouth isn't designed for such but he knows English and Japanese, can read, and can find other ways to communicate when the structure of his mouth works against him.
Adventures of Rex the Wonder Dog Vol 1:
- Alien Hair: Xtar and the rest of the aliens from Yquem are entirely hairless fairly humanoid pink people, with large black eyes, huge ears and a somewhat bulbous head.
- Aliens Speaking English: O-Tar and Elan, as well as the cat-like species from Lamenor's moon, all seem to speak English.
- Animal Talk: Played with. Usually Rex is the only animal whose thoughts and communication attempts are shown, but when other animal's communication attempts and thoughts are shown they are much less complex as they're still just animals even if they and Rex can usually understand each other to a degree. In later issues all dogs talk to each other in complex flowery speech, but at the beginning there was a clear and stark difference between Rex and other animals.
- Cheaters Never Prosper: A man tries to cheat at a bet he made with Danny's uncle Everett, and takes more and more extreme criminal actions as Rex ensures his plans fail leading to his imprisonment for attempted murder.
- Crazy-Prepared: Elaine Cole, the woman dating Danny's uncle Jim, seems to carry a well stocked first aid kit with her at all times.
- Dad the Veteran: Danny's father is a WWII veteran, and is still in the army when the story starts.
- Easy Amnesia:
- Rex forgets his name and life after hitting his head, but remembers after hitting his head again.
- Rex helps track down a missing US scientist who somehow forgot his identity and was mistaken for a member of the French Foreign Legion. Dr. Peter Weston then remembers who he is upon hearing his name.
- Everything's Better with Monkeys: Fellow intelligence boosted animal Detective Chimp has a backup feature.
- Has a Type: Danny seems to develop an instant crush on every blonde girl he meets that's close to his age. He usually does nothing with these feelings though and just tries to befriend them like he does just about everyone.
- Heroic Canines, Villainous Felines: Played with, in that a criminal uses the idea that Rex is smelling the sent of cat rather than clues to a crime on several occasions meaning cats are coincidentally aiding criminals just by being around. Mountain lions are occasional antagonists, especially in issues taking place on a ranch or farm. The feline like aliens on Lamenor's moon on the other hand play it straight since they're planning on attacking O-Tar's people after making a false alliance with them.
- Heroic Pet Story: The story of a pet dog who is also a superhero.
- Hollywood Fire: Rex rescues a number of people from dramatic fires, from forest fires to apartment fires.
- They Have the Scent!: Rex will often catch a criminal's scent and take off tracking them down for a dramatic chase and confrontation.
- Timmy in a Well: Parodied when Rex is trying out for a part in a movie by "saving" a perfectly safe Danny from a pit on set. Most of the time when Rex becomes aware of someone needing saving he just saves them rather than try to communicate something complex to his owners, they know he's more intelligent and capable than a normal dog but he has a hard time letting them know more than that they should follow him or look at what he's gesturing towards.
- Tropey, Come Home: Rex looses his memory after hitting his head while saving a particularly daft kid from a train and he wanders and tries to figure out what he's forgetting while Danny searches for him.
- What Happened to the Mouse?: In one of the several stories that take place during WWII Rex works alongside a fellow Super Soldier dog, though the other is less fully trained and a little younger and more impulsive than Rex. This dog is never seen or mentioned again, and the retread of Rex's origin that states the serum that created him was destroyed after he took it makes it seem like he never will be.