A normal amount of sargassum. (Photo: James St. John/Flickr)

If you like your postcards scrawled on, we’ve got the vacation for you. Beaches in the Caribbean and Barbados have become snarled in ridiculous amounts of sargassum, a brown, bubbly seaweed that tends to clump into huge mats. While at their blooming site in the Sargasso Sea, the weed mats house tuna, crabs, turtles, and other beloved seafarers. But after they get beached, they’re more likely to attract flies, suffocate fish, and repel tourists. 

Sargassum mats where they belong, in the Sargasso Sea. (Photo: Tam Warner Minton/Flickr)

Artfully strewn shreds of sargassum have long graced the Caribbean coastline, but these whole-beach takeovers are pretty new—some beaches report ten-foot pile-ups, which is enough to make an incredible number of sea monster wigs. Some scientists blame these “bumper crops,” which started showing up in 2011,  on runoff filled with sewage waste and fertilizer. Others think the mats are actually from the equatorial Atlantic, where warming water has mixed with river-carried nutrients to make Sargasso-like conditions. 

Too much sargussum can also snare larger animals, like this spinner dolphin, caught in 2010. (Photo: Terry Ross/Flickr)

People may spar over exactly where it came from, but everyone agrees on one thing: it stinks. The Washington Post described it as ”smelly and decaying,” while The Associated Press evokes ”stinking mounds” that “attract biting sand flies and smell like rotten eggs.” Tobago is calling it a “natural disaster,” and Mexico has pledged $9.1 million and thousands of temporary workers to shovel it away—although at the current rate of entanglement, odds are it will be quickly replaced.

Every day, we track down a fleeting wonder—something amazing that’s only happening right now. Have a tip for us? Tell us about it! Send your temporary miracles to [email protected].