In answer to the same question, which we received here at the American Folklife Center (Library of Congress), we located a story called "The Poopampareno" on pages 518-19 of Benjamin Botkin's _A Treasury of Southern Folklore_. In this story, a prideful hunter went out into the woods alone, thinking that he could do without his faithful dogs. He was soon treed by a terrible saw-toothed creature called a Poopampareno, who began gnawing at the tree trunk to fell the tree and eat the hunter. The hunter twice calls to his dogs "Here, Sambo! And Ringo! Your master's almost gone! And a poo-pam and a poo, and a poo-pam and a po-o-o." The second time the hunter calls them, the dogs hear him and rush to his rescue, killing the Poopampareno just in the nick of time.

Botkin's footnote for this story says "By Julia Beazley. From Coyote Wisdom, edited by Frank Dobie, Mody C. Boatright, and Harry H. Ransom, Texas Folklore Society Publications, Number XIV, pp. 252-254. Copyright, 1938, by Texas Folk-Lore Society. Austin. The story of the terrible and wonderful poopampareno I heard from the Reverend Mr. Werlein, rector of Eastwood Community Church in Houston, who told it at a children's story hour. As he told the story, with action finely suited, he gave the line, 'Here Sambo! And Ringo!' a kind of 'Old Black Joe' tune - J.B."

I hope this is the information you were seeking...albeit many years later!

Jennifer Cutting, American Folklife Center