An appeal to pity (also called argumentum ad misericordiam, the sob story, or the Galileo argument) is a fallacy in which someone tries to win support for an argument or idea by exploiting his or her opponent's feelings of pity or guilt. It is a specific kind of appeal to emotion. The name "Galileo argument" refers to the scientist's suffering as a result of his house arrest by the Inquisition.
An appeal to pity can be seen in many charitable advertisements. Charities appeal to your pity of less fortunate people in order for you to be more likely to donate to that particular charity.
Recognizing an argument as an appeal to pity does not necessarily invalidate the conclusion or the factual assertions. There may be other reasons to accept the invited conclusion, but an appeal to pity is not one of them (see also Argument from fallacy).