Sergeant Stubby was a stray, homeless mutt who saved more lives, saw more combat, and performed more badass feats of heroic awesomeness than most people could ever hope to accomplish even WITH the advantage of prehensile thumbs and the ability to utilize 100 percent of their brain power without exploding into a burst of ball lightning.
The American version of Voytek the Soldier Bear, this fearless, ass-destroyingly ferocious Pit Bull Terrier started his humble life as most stray animals do hungry, cold, alone, and stranded in the town of New Haven, Connecticut. Living garbage can to garbage can without so much as a doghouse roof over his head, one day this poor dejected little canine happened to stumble onto the parade ground on the campus of Yale University, where it just so happened that the men of the 102nd Regiment, 26th Infantry Division were training for their eventual deployment to fight in World War I. The so-pathetic-it's-adorable little dog-creature was taken in by a soldier named John Robert Conroy, who named the pup "Stubby" on account of the thing's little stumpy gimp tail (or maybe this is a common trait of pit bull terriers, I have no idea). Conroy started leaving food out and let the little guy sleep in the barracks from time to time, and before long pretty much every dude in the 102nd thought this thing was omg totez adorbs, etc. The dog, for its part, was also like insane-as-hell smart, and I don't mean like, "Oh hey that dog thinks he's people because he sits in an armchair and licks beer coozies" stuff, but more like, "Holy crap balls Lassie's trying to tell us that Little Timmy fell down a well and is being slowly digested by a thousand rabid snakes sent forth from a rift in the Hellmouth," smart. After just a few weeks of hanging around the drill field, watching the soldiers do their thing, this friggin' dog/Battle-Cat hybrid learned the damn bugle calls, could execute the marching maneuvers with the men, and was I shit you not trained to salute superior officers by raising his forepaw to his brow in what I can only imagine was a sight so cripplingly adorable that nowadays it would be an obnoxious, long-running Internet meme on one of these I Can Has Catburger websites.
Private Stubby had free reign to drink out of any toilet bowl on the Yale campus during training, and when the order came down for the 102nd to ship out to battle Conroy just stuffed the dog into his greatcoat and smuggled him on board a ship bound for France. Once the transport was under way, Conroy brought the dog out onto the deck, and all the sailors all decided this dog was so totally flippin' sweet that they had a machinists' mate make him a set of dog tags to match the ones worn by the soldiers. When Conroy got a little sloppy and his weirdo covert dog smuggling operation was discovered commanding officer, Conroy gave the order to, "Present Arms," the goddamned dog saluted the commander. The officer was like "WTF ever" and from that point on Stubby was officially allowed to follow Yankee Division out to the battlefront.
This is where it gets good. Stubby became the official mascot of the American Expeditionary Force, and did his part to raise morale to the war-weary soldiers on the front lines. Ok, that's great, but during his tour of duty in Europe, Stubby also participated in 17 battles and four major offensives including the St. Mihel, Meuse-Argonne, Aisne-Marne, and Champagne Marne campaigns. In February 1918, while fighting in a heated sector north of Soissons, Stubby found himself under constant artillery and sniper fire for over a month straight with no respite, responding by howling and barking in "a battle rage" every time gunshots started ringing out. He was wounded in action later that month in a chemical weapons attack, when the Germans launched some mustard gas that poisoned the little dog so hard it nearly died.
But this was a badass pit bull, and it would take more than a lung full of poison gas to slow him down. Instead of croaking, Stubby became more hardcore he'd had his fill of getting the crap kicked out of him by chemical weapons, and thanks to his heightened sense of smell this little bastard could now sniff out mustard gas before it became lethal. From that point on, any time a gas canister exploded near American lines, the friggin' dog would run up and down the trenches barking and biting men until they put their gas masks on, an act that saved countless lives. Once his comrades were properly masked-up, Stubby would run and hide until the gas cloud cleared (because this was back in the days before they'd invented doggy chemical warfare hoods).