An Army regiment that unsuccessfully sought to make use of the swamp dragon in battle. Its last commander, indeed its last surviving trooper, is Colonel Charles Augustus Makepeace, author of the stirring military memoir Twenty-four Years Without Eyebrows.
He had known Lady Sybil Ramkin at the start of this venture and she had warned that it would be totally impossible to breed dragons stable enough for warfare. She was of course right but in true military fashion they piled dreadful failure on top of failure for twenty-odd years.
The Colonel’s discussion with Vimes at dinner was cut short by his wife so no explanation was given on how the regiment intended to use these living flame throwers. As a breed dragons are small enough to carry but given the heat of their flame and tendency to explode herding may have been safer.
Colonel Makepeace has retired but still keeps a few dragons as he says ‘a day without a singe is a day without sunshine’. They save on matches as well.
Picked this up on tvtropes and I am now looking for confirmation and further details...
In another attempt at weaponizing animals, the Swedes once attempted to create a unit of moose cavalry (Sweden having a limited supply of good cavalry horses but plenty of moose) in the 17th century. It turned out that 1: Moose can't just subsist on hay like horses can, 2: Once the moose are in rut, they'll attack everybody, even their handlers, 3: Moose are terribly vulnerable to a wide variety of livestock diseases, and 4: Moose are smart enough to figure out that guns and pikes are bad for their health, and once they do, they refuse to go anywhere them. The unit was dissolved without ever fighting a single battle.
This is useful... Moose Cavalry.