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."