Indescribable! Indestructible! Nothing Can Stop It!

So said the posters for The Blob, the locally made cult-horror hit produced by Philadelphia native Jack Harris, who died Tuesday. He went to produce other movies (like The Eyes of Laura Mars starring Faye Dunaway and Tommy Lee Jones), but his biggest hit was The Blob, filmed at Valley Forge Studios and in Chester Springs, Royersford, and  Downingtown, and at the Colonial Theater in Phoenixville, which famously holds a Blobfest every year, with fans running out of the theater, re-enacting the movie's most famous scene.

The Blob become an indestructible hit when released in 1958. Made for a few hundred thousand, it grossed $4 million in Eisenhower-era dollars. You can — and should — still watch it; it's available on Amazon and iTunes.

Its success is describable, and has to do with other blobs of its day – the growing mass of teen Baby Boomers who needed something to do, and the corresponding ooze of movies that catered to them.

These movies had titles like Attack of the Crab Monsters (1957), I Was a Teenage Werewolf (1957), The Wasp Woman (1959), and A Bucket of Blood (1959). As film historian Tim Dirks notes: "Young people attended outdoor drive-ins that showed exploitative, cheap fare."

Jack H. Harris, the producer of 'The Blob,' died Tuesday at 98.

Drive-ins peaked in the late 1950s, when there were more than 4,000 operating in the United States. They were called "passion pits," and the teens who frequented them found things to do in the privacy of the front seat that were not necessarily related to their passion for cinema.

The Blob originally was intended to be the also-ran in a double feature headlined by I Married a Monster From Outer Space, but proved so popular it quickly vaulted to top billing.

Its reception with critics was cool. The New York Times said the picture "talks itself to death" and described the special effects as "phony."  Take that with a grain of salt:  The reviewer also didn't think much of the young star, Steve McQueen, who'd be a major international star within a decade.

McQueen stars in the film (his character is imaginatively named Steve) as a teen — though he was 28 at the time — who is making out with his girlfriend (Aneta Corsaut), activity interrupted by the crash of a meteor. (The movie originally was titled The Molten Meteor.)

The meteor contains a gelatinous alien amoeba (during production, it variously was called "the mass," then "the glob," and, finally, "the blob") that engulfs humans, growing as it does, consuming doctors, nurses, a guy in a grocery store, folks in a diner, a movie theater. Eventually, Steve deduces the blob can't handle cold and subdues it with fire extinguishers, and the government drops it well above the Arctic Circle.

The Philadelphia Inquirer's 1958 review of "The Blob."

That's that, someone says. To which McQueen replies: 'Yeah, as long as the Arctic stays frozen."

The movie, like many of its day (Invasion of the Body Snatchers), has been cast as a Cold War metaphor, playing on cultural fears of Soviet communism. The movie's screenwriters found this idea laughable. More likely, there is a primal, durable appeal in the idea of an all-consuming entity like the blob – it inspired a sequel in 1972 and a remake in 1988.

Nothing can stop it, because it's endlessly adaptable. The blob absorbs and consumes everyone it touches, and the more people it touches, the more it spreads, the bigger and more inexorable it becomes.

Today, we know it as Facebook.

This article draws on material found in the digital archives of The Philadelphia Inquirer and Philadelphia Daily News. Search the archives for yourself and subscribe for full access.