A motion to strike is a request which can be made by either party in a legal case to ask that part or all of a pleading submitted by the other party be thrown out and removed from the record. This includes complaints and answers to those complains. Motions to strike can also be made to remove evidence or testimony from the record.
Attorneys make a motion to strike because they believe that the information or statement in question is problematic in some way. It may not be relevant to the case. It could be clearly erroneous, and not allowable under the rules of the court, or defamatory. A person filing a motion to strike must explain why the motion is being filed and provide evidence to back up the request. The target of the motion has an opportunity to respond. Once both sides have had a chance to be heard, the judge can make a ruling on the matter.
Before a trial even begins, attorneys from both sides prepare documents which are seen by the other, including complaints and answers. Written motions to strike may be filed during this period to remove objectionable parts of a complaint or response so that these matters are cleared up before the attorneys meet in court. Once struck, the information cannot be brought up in court and is no longer considered part of the case.
In court, a motion to strike can be filed orally with the judge if an attorney has an objection to a statement made by a witness. In this case, the judge reviews the situation to decide whether or not the motion is legally valid. If it is, the judge indicates that the motion has been granted and instructs the jury to disregard what it has heard. Legal scholars have pointed out that, no matter what the intentions of such instructions are, jurors inevitably retain the information and that it can become prejudicial in nature. If a witness has an outburst on the stand which is struck, the jurors will still remember what happened.
Courtroom dramas often play up the motion to strike in the courtroom setting, with lawyers popping up and down and shouting "objection" during testimony. Despite what the television shows, lawyers must file motions to strike in an orderly fashion which does not disrupt the court, and some of the more fantastical activities depicted on television are not seen in real courtrooms. Attorneys can even be fined for contempt of court for violations of courtroom procedure.