On Wikipedia, vandalism is the result of a user doing bad edits to Wikipedia. Users who do vandalism on Wikipedia are trying to damage Wikipedia on purpose. Vandals are users that do vandalism. Wikipedia does not accept vandalism. Vandals are usually blocked by Wikipedia's admins. Vandalism on Wikipedia is an example of trolling.
Some vandals may add nonsense or joke around in a bad way. Others may try to remove content, or they may replace good content with bad content, such as hyperlinks that can lead to abusive or offensive content. There are some vandals that edit Wikipedia so that they can attack other people or add offensive content. Some vandals try to add intentionally wrong content, called hoaxes, which make Wikipedia look misleading.
Wikipedia tries their best to allow all pages to be edited freely.[1] Because anyone can edit Wikipedia, it is easy for a vandal to destroy a page,[2][3] with the exception of protected pages. Admins can protect a page to prevent some users from editing that page, which can reduce vandalism but also may prevent some good edits. There are some Wikipedia bots that can detect and remove vandalism faster than any human editor.[4]
Some vandalism attempts on Wikipedia have ended up being notable. The Seigenthaler incident was a major incident on Wikipedia that happened in May 2005, because a user wrote false and shameful statements on a biographical article about John Seigenthaler, Sr.[5]