Ad Hominem
An ad hominem fallacy uses personal attacks rather than logic. This fallacy occurs when someone rejects or criticizes another point of view based on the personal characteristics, ethnic background, physical appearance, or other non-relevant traits of the person who holds it.
Ad hominem arguments are often used in politics, where they are often called "mudslinging." They are considered unethical because politicians can use them to manipulate voters' opinions against an opponent without addressing core issues.