A persondescribed as manifesting paranoia and delusions of persecution. Also used for a person considered violent and/or creepy. Origin of word believed to be alternative site chatrooms.
Verb variant is "Maced". used to describe long meandering postings demonstrating the above characteristics.
The individual that posts a 30 line message about gay space aliens plotting to take over the earth and how the aliens are plotting with government officials to destroy him is called a Mace. The post is referred to as "Oh the forum was Maced".