Talking Purse

The Talking Purse was the purse of the troll William. When Bilbo Baggins tried to pick the purse from William's pocket, the purse suddenly squeaked "Ere, 'oo are you?". William was thus warned of the pickpocketing and captured Bilbo.
The size of the purse was huge: it is told to have been "as big as a bag to Bilbo". Apparently "Trolls' purses" were known for their mischief.