The 1998 East Java ninja scare was an outbreak of mass hysteria in East Java, Indonesia, in which the local population believed they were being targeted by sorcerers. In response, unidentified vigilantes, known as ninja due to their all-black garb, killed a number of suspected sorcerers, including religious leaders. In response to these killings, other Indonesians attacked and killed suspected ninjas. The scare began in February, with most of the deaths during the scare occurring between August and September.
The killings largely ended by the end of 1998; however, another group of similar killings occurred in December 1999.
According to the National Commission on Human Rights, 307 people were killed during the scare in total: 194 people in Banyuwangi, 108 in Jember, and seven in Malang.