Fantastic Fables by Ambrose Bierce: The Tyrant Frog
The Tyrant Frog
A SNAKE swallowing a frog head-first was approached by a Naturalist with a stick.
"Ah, my deliverer," said the Snake as well as he could, "you have arrived just in time; this reptile, you see, is pitching into me without provocation."
"Sir," replied the Naturalist, "I need a snakeskin for my collection, but if you had not explained I should not have interrupted you, for I thought you were at dinner."