What did Tip make specifically to frighten Mombi in the novel, The Marvelous Land of Oz?

From the text:

There were pumpkins in Mombi’s corn-fields, lying golden red among the rows of green stalks; and these had been planted and carefully tended that the four-horned cow might eat of them in the winter time. But one day, after the corn had all been cut and stacked, and Tip was carrying the pumpkins to the stable, he took a notion to make a “Jack Lantern” and try to give the old woman a fright with it.