Tom snaffled the chocolate on the desk when the teacher wasn't looking.

snaffled 是动词 snaffle 的过去式。snaffle 是英式俚语，意思是"偷偷拿走、顺手牵羊"，通常指未经允许悄悄拿走小东西的行为。这个词带有轻松诙谐的语气，多用于非正式场合。