Crime of Self Defense

Arnie has just beaten off a murderous attack by Bob. Plot over, Bob goes to jail, roll credits, right?

Wrong. Maybe Arnie was bigger, or stronger, or could conceivably have run away. Either way, someone in a position of authority feels that Arnie was in the wrong inflicting whatever damage he did to Bob. Bob, on the other hand, is a poor victim. Cue drama.

This often involves Double Standard Abuse (Female on Male); sometimes, it's due to Selective Enforcement. Compare Can't Get Away with Nuthin', Wounded Gazelle Gambit. An attacker may even play a Deliberate Injury Gambit to invoke this trope. A history of such cases In-Universe may explain occurrences of Once Is Not Enough.

As with everything else law-related, expect the writers to interpret self-defence laws creatively.

No Real Life Examples, Please

Anime & Manga

 * In My Hero Academia, it's illegal for someone to use his/her quirk (superpower) against another person unless the person using it has a hero license.

Comic Books

 * This is the entire conflict between the X-Men and their nemesis, Magneto. The X-Men wholeheartedly believe in this ideal, as taught by their leader, Professor Xavier. Magneto, on the other hand, believes that the only way to battle oppression is to rise up and conquer them. Various points of media will show either as being "right", Depending on the Writer.

Film

 * In Con Air, the (sympathetic) main character is put in prison for accidentally killing someone in defense of his wife, but you get the impression he got a raw deal, and the judge says that as an inactive soldier, he should have been more careful.
 * An especially jarring plot point from The Butterfly Effect has Evan get sent to prison when he accidentally kills Tommy in self-defense. Mind you, everyone knows Tommy is a violent psycho and there were a dozen witnesses to testify that Tommy was trying to kill Evan.

Literature

 * In Harry Potter, Harry risks breaking The Masquerade by using magic to protect his cousin and himself against Dementors, and is put on trial for this. In this case, the government in question is waging a propaganda war against Harry, and is twisting the law in order to punish him as much as possible and make him look like a delinquent.
 * In Hoot, Roy punches Dana in the face while being choked and is subsequently punished
 * Honor Harrington takes some flak with her political opponents for shooting a man when she knew his gun was empty,.
 * The Dresden Files: Harry Dresden almost got executed for killing his Evil Mentor (who had tried to mind control and then kill him), because the White Council believes that killing using magic automatically warrants death, only somebody being willing to sponsor him saved him. And he still spent the next couple of decades being repeatedly accused of Black Magic.

Live Action TV

 * Season two of Dexter has his girlfriend's abusive ex-boyfriend force his way into her house. Her children are sleeping nearby, and she's afraid of what will happen to them if she puts up a fight, so she lures him into her bedroom, and smacks him down with the Emergency Bat she keeps under her bed. Next thing you know, the ex-boyfriend is filing assault charges against her, and she's in danger of losing her kids. Fortunately, her current boyfriend just happens to be a psychopathic Serial Killer Killer...

Web Comics

 * In a strip of Ozy and Millie, their regular Jerk Jock bully, Jeremy, keeps pushing Millie into a pool of mud, knocking her over every time she tries to get up. Finally, she snaps and socks him in the face... at which point a teacher immediately spots her, and hauls her into the principal's office for starting a fight. (The injustice inherent in the school system is a frequently visited theme).
 * Girl Genius made a running gag early in its run about everyone being mad at Gil for killing doctor Beetle (by batting his own bomb back at him), and Gil defending himself by saying, "He threw a bomb at me!"
 * In Muertitos, the school has a zero tolerance policy. After a girl bully attacks him, Honeo is suspended because instead of lying limp, he flailed around and could have hit someone, but the bully got off scot free because her dad is rich and regularly makes donations to the school. You can see the strip here.