1999: For weeks, the Philippines was rife with rumours of a military plot to unseat the country’s unpopular president, Joseph “Erap” Estrada. When the lights went out in Manila and across much of Luzon on the evening of 10 December, jittery Filipinos thought a coup was under way, until Estrada popped up to show he was still in charge. The electrical blackout had in fact been caused by jellyfish: tons of jellyfish had clogged the cooling water intake of a power plant in Pangasinan.
Source: Lisa-ann Gershwin, Stung!: On Jellyfish Blooms and the Future of the Ocean (2013), pp. 13–14