Ultra Flare

the Ultra Flare (ウルトラフレア) was an apocalyptic incident that happened in Ultraman X, which set 15 years prior to the series.

Ultraman X
One night, an unusual purple solar flare bathed the Earth but during the event, it triggered all OOPArts from around the globe, thus awakening the slumbered Spark Dolls that caused worldwide panic. Due to the incident, Xio was formed to combat monster threats and supervised other paranormal activities should the Ultra Flare initiated again.

Trivia

 * The Ultra Flare event is an inversion from the Dark Spark War in Ultraman Ginga. Whereas all Ultra Kaiju and Ultra Heroes entered themselves in a battle against each others and turned into Spark Dolls, the event here is reversed.