"Certainly, answered the man;"here, bring me a blanket and a good-sized mallet."

Explanation

This is correctly used as the object in the second part of the dialogue. There is no error with "mallet."Corrected Sentence:"Certainly," answered the man, "Here, bring me a blanket and a good-sized mallet."By correcting the punctuation and capitalization, the sentence becomes grammatically correct and the dialogue is properly presented.