Toward the end of summer 1888, a monster stalked the streets of London’s Whitechapel district, butchering five women and ensuring the neighborhood’s name would be forever linked with that of Jack the Ripper. Some 130 years later, darkness returned to Whitechapel—only this time, the monster lurked underground, stretching to a length of 850 feet and weight of 130 tons (for some perspective, that’s roughly the load of a blue whale).

Unlike Jack the Ripper, this modern-day specter—better-known as the Whitechapel fatberg—was easily identified and contained. In fact, Mark Brown reports for the Guardian, the Museum of London now offers a 24/7 livestream of the fatberg, enabling interested parties to observe its captivity from the comfort of their own homes.

Workers chanced upon the fatberg, a massive clump of congealed fat, wet wipes, diapers and miscellaneous waste, while conducting a routine inspection of London’s sewage system last September. According to a separate piece in the Guardian by Matthew Taylor, the toxic concoction could've wreaked havoc on the city, flooding the streets with raw sewage and spreading infectious bacteria such as E. coli.

Instead, personnel clad in protective gear and armed with shovels and jet hoses spent nine weeks extracting the fatberg, according to Jill Lawless of the Associated Press. Most of the concrete-like mass was broken up and converted into biodiesel, but two slices landed at the Museum of London, where they served as the main attraction in a temporary exhibition that went on view earlier this year.

According to the Guardian’s Brown, the fatberg drew hordes of equally intrigued and disgusted visitors. Rather than remaining stable like most museum artifacts, the toxic clump underwent a series of changes befitting that of a monstrous, suspiciously sentient being. Its color changed from dark brown to grey, then beige. “Sweat,” produced by moisture trapped within the fatberg, laced the walls of its case with condensation. Coffin flies, which are known to feed on decaying matter, hatched and flitted across the structure’s porous surface.

Although visitors weren’t allowed to smell the fatberg firsthand—due to the substance’s volatility, the museum’s two samples were held in virtual quarantine, sealed within a three-box system and handled only by staffers wearing full-body protective suits—curator Vyki Sparkes tells the AP’s Lawless that the fatberg initially smelled like a used diaper “that maybe you’d forgotten about and found a few weeks later.” By the time the exhibition opened, its scent had transformed to that of a dirty toilet.

“Here at the museum we are all about reflecting the real lived experience of Londoners, and it is part of our season exploring the highs and lows of London city life,” Sparkes tells Brown. “I don’t think you can get much lower than a fatberg.”

To sewage engineers, Sparkes’ critique is apt: As Matt Rimmer, head of Thames Water’s waste networks, notes in a statement, fatbergs are the direct result of human activity. “These situations are totally avoidable,” he states, “and [are] caused by fat, oil and grease being washed down sinks and wipes flushed down the loo.”

According to BBC News’ Sean Coughlan, wet wipes—often misleadingly marketed as “flushable”—constitute 93 percent of fatbergs and similar sewer-blocking substances. Fat, oil and grease, as well as feminine hygiene products, plastic wrappers and toilet paper further contribute to fatberg formation.

The fatberg “shows our disgusting side,” Sparkes declares in a blog post for the Museum of London. “It is hidden away, getting worse and worse as we pile the accumulated sins of the city into it: cooking fat, condoms, needles, wet wipes, and of course human waste.”

Since the exhibition’s close, an unusual toxic mold visible in the form of yellow pustules has overtaken the fatberg. To see the mold in action, visit the museum’s “FatCam,” which will keep you updated on all of the latest developments. And, if the livestream isn’t enough to satiate your fatberg feelings, an upcoming stage show (working title Flushing Fatbergs!) is readying to bring the Whitechapel beast from the sewer into the spotlight.