What is a ‘fatberg?’ In more or less words, it’s one of the most nauseating things a person could see.

[Editor’s Note: Don’t continue to read unless you’ve already eaten. After learning about the “fatberg” that was blasted out of London’s sewer system digesting food might be a difficult task.]

Utility company Thames Water discovered the biggest “fatberg” in Britain’s history, the Associated Press wrote Tuesday. “Given we’ve got the biggest sewers and this is the biggest fatberg we’ve encountered, we reckon it has to be the biggest such berg in British history,” The New York Daily News quoted Water waste supervisor Gordon Hailwood.

A “fatberg” is congealed fat and baby wipes. The one recently found in a London sewer was about the size of a double-decker bus and nearly 15 tons. According to AP, Thames Water said the mound formed from "wrongly flushed festering food fat mixed with wet wipes” and was located under a road in London’s southwest town Kingston.

“We’ve never seen a single, congealed lump of lard this big clogging our sewers before,” Hailwood added. “It was so big, it damaged the sewer and repairs will take up to six weeks,” he said.

If fatbergs are left untreated they can cause backups and floddings, Thames Water told the AP.

Fatbergs aren’t uncommon in London, but this recent lump of lard was exceptionally big and will hopefully make Londoners think twice about what they flush down the toilet.  According to the Daily News, it took 10 days in order for the blob to be cleared from the drain.

Instead of breaking down like toilet paper, baby wipes stick to fatty liquids, like cooking grease if it is inappropriately poured own kitchen drains, thus creating the fatberg. British citizens are now being encouraged to “bin it, don’t block it,” to avoid future murky monstrosities in their sewers, the Daily News added.

Check out footage of the fatberg below: