Mr. Jackson in Beatrix Potter's "The Tale of Mrs. Tittlemouse,” e.g. (4)
I believe the answer is:
toad
(Other definitions for toad that I've seen before include "Froglike animal or repulsive person" , "Wind in Willows hall-owner" , "Contemptible person" , "Amphibian with warts" , "Hall proprietor (Grahame)" .)