"a warlike mouse came down"

. . . to the water to take a drink, and upon being accosted by a regal frog, let him know this:

The mouse, speaking haughtily, said: “I am Crumb Snatcher, and my race is a
famous one. My father is the heroic Bread Nibbler, and he married Quern Licker,
the lovely daughter of a king. Like all my race I am a warrior who has never
been wont to flinch in battle. Moreover, I have been brought up as a mouse of
high degree, and figs and nuts, cheese and honeycakes is the provender that I
have been fed on.”

And pride goeth before a fall, with a short wet trip on a royal frog in between. For the full story of The Battle of the Frogs and the Mice (from The Golden Fleece's chapter on The Life and Labors of Heracles - it's a crazy story Heracles hears from some robbers. Courtesy of Bartleby.com.)

Bread Nibbler struck the first blow. He fell upon Loud Crier the frog, and overthrew him. At this Loud Crier’s friend, Reedy, threw down spear and shield and dived into the water. This seemed to presage victory for the mice. But then Water Larker, the most warlike of the frogs, took up a great pebble and flung it at Ham Nibbler who was then pursuing Reedy. Down fell Ham Nibbler, and there was dismay in the ranks of the mice. Then Cabbage Climber, a great-hearted frog, took up a clod of mud and flung it full at a mouse that was coming furiously upon him. That mouse’s helmet was knocked off and his forehead was plastered with the clod of mud, so that he was well-nigh blinded. . .