Character Analysis
Squeak is one of the master-at-arms' "more cunning corporals," known for his squeaky voice and ferreting movements (13.1). Claggart recruits him to do his dirty work: to spy on Billy Budd and report back to him.
The problem is that Squeak, "having naturally enough concluded that his master could have no love for the sailor," decides to elaborate on the stories he knows and to make up epithets about Claggart and put them in Billy's mouth (13.3). Squeak has a very small role in the story, but his ugly ambition is part of the reason that Claggart is able to frame Billy.