The Double Event was predicted by K-Science officer Hermann Gottlieb, who believed that the increased number of Kaiju attacks suggested that the Breach that connected Earth to the Anteverse was stabilizing and would allow for more than one Kaiju to exit the portal at once.
According to Gottlieb, the "throat" of the Breach was becoming wider to accommodate the size of Kaiju classified as Category III and IV. The Double Event would be followed by a Triple Event, with three Kaiju exiting the Breach at the same time. The latter would herald the predicted extinction-level event that would wipe out humanity.
Hong Kong Incident
On January 8, 2025, the first Double Event occurred when two Category IV Kaiju codenamed Leatherback and Otachi emerged from the Breach and attacked Hong Kong, proving Gottlieb's theory correct. While on approach to the city, the two Kaiju fought the Jaegers Cherno Alpha, Crimson Typhoon and Striker Eureka, and eventually overpowered all three. Fortunately, before the two Kaiju could destroy Striker Eureka and lay waste to Hong Kong, Gipsy Danger arrived on the battlefield and was able to kill them both in separate engagements.
Hannibal Chau theorized that the Double Event was provoked when Newton Geiszler recklessly drifted with the partial brain of the Kaiju Mutavore, having neglecting the fact that the Drift is a shared connection.
The proceeding Triple Event occurred during Operation Pitfall when two Category IV Kaiju, Scunner and Raiju, and one Category V Kaiju, Slattern, emerged from the Breach in response to the Pan Pacific Defense Corps's attempt to destroy it using a thermonuclear bomb. Despite the fact that they were outnumbered 3-2, Gipsy Danger and Striker Eureka ultimately prevailed against the Kaiju and were able to successfully destroy the Breach as planned, albeit at the cost of both Jaegers and the lives of Striker Eureka's pilots.