Every year, a warming Pacific Ocean trend known as El Niño threatens weather anarchy across much of the planet: torrents of rain and mudslides in Southern California, snow in Guadalajara.
Most of the time, people just whip out their extreme weather gear. But this upcoming El Niño, dubbed "Godzilla" by someone who would know, is threatening to be the biggest the world has seen in nearly 20 years.
Here's everything you need to know.
This year, NASA Jet Propulsion Lab scientist Bill Patzert created the term "Godzilla El Niño" to describe the weirdly large weather pattern currently forming in the eastern Equatorial Pacific--a patch of warm water so huge that it's already causing phenomena of biblical proportion.
Let's start with the influx of hammerhead sharks.
The arrival of a huge blob of warm water right off of our left coast is bringing its own adorably deadly ecosystem with it, including great white and hammerhead sharks in greater numbers.
"Big predators are coming back, and that includes seals, sea lions, sharks and all the things we never had to share the waves with," Chris Lowe, a marine biology professor at Cal State Long Beach, recently told the Los Angeles Times.
According to the NOAA, El Niño events tend to mean bad news for seal populations in California.
For example: The 1983 El Niño caused the northern fur seal birth rate to drop 60 percent compared with the previous year. And the pups that were born did not survive.
This year, record numbers of starving baby sea lions have been washing ashore in California, again, thanks to El Nino.
Scientists suspect that El Niño's warm waters are cutting off key food sources, causing mother seals to leave their pups on their own while they hunt for food.
The last time we saw an El Niño this big (circa 1998), it turned parts of Southern California into one big mudslide. Entire mansions became mobile homes...and not in a good way.
El Niño is also sending less-common whale species closer to the West Coast this year. Humpback whales, for example, already have been seen off the coast of Oregon, searching for food.
Big El Niños also tend to mean flooded streets. The streets in Bangkok turned into rivers during the 2006 El Niño.
Another thing that happened the last time we had an El Niño this big: Death. The 1997-1998 El Niño killed an estimated 16 percent of the world's reef systems.
The last mega-El Niño also sent a wave of wet weather into north-eastern Kenya. That, in turn, spurred a spike in Rift Valley fever. About 400 Kenyans died of Rift Valley fever in 1998.
Think we're exaggerating? Well, the left image shows a heat map of the Earth in October 1997, the year of the last mega-El Nino. The image on the right? That's what the earth looks like in 2015.
Along with mudslides and floods, big El Niños are known for felling trees during storms. Lots and lots of trees.
California cities this year have been ordered to cut water use by 25 percent, a directive that could distress the state's trees and cause even more of them to collapse during a heavy El Niño rainy season.
You're probably wondering just how big this storm is. No problem.
This year's patch of warm water is about 300 to 400 meters deep, and four to six times the size of the continental United States.
There is one factor that might keep El Niño from reaching Godzilla status this winter: trade winds. Those winds usually keep warming water and air in the Pacific from moving east. When those trade winds collapse, the yearly El Niño forms.
There's always a chance that this year's trade winds could decide to stick around. But if they decide to collapse, a Godzilla El Niño is more likely.
If you're hoping that El Niño's rains will at least cure the California drought, you're wrong...
"There's what I call the El Niño drought-busting myth," Patzert says. "Only 7 percent of California's yearly rainfall is delivered by El Niño. El Niño does deliver rain, but also floods, mudslides, mayhem. Be careful what you wish for."
Let's just say that our trade winds don't collapse completely. Maybe they only collapse a little.
Even if the Godzilla El Niño turns out to be closer to Godzuki, the weather could still be miserable. The 2007 El Niño season saw record heat in California, but no rain to go with it, causing weird phenomena like these odd colors in a Southern California reservoir.
Other countries who happen to be suffering from droughts might also get relief. This 2007 rainbow came courtesy of a super-heavy El Niño rainy season for Australia.
Like any good monster, the Godzilla El Niño also has an arch-nemesis, another weather system that could threaten its strength and glory. Patzert and others call it "The Blob," a separate patch of warm water parked farther north, off of the US West Coast.
That patch of water is associated with a very strong ridge of atmospheric high pressure (dubbed the Ridiculously Resilient Ridge by scientists) that can push storms farther north and east. In other words, the Blob and its sidekick, the RRR, are poised to possibly counteract many of Godzilla El Niño's evil plans for North America.