Is Sphere the worst movie of the last twenty years?

The movie we watched last night, Sphere, was so bad, it got me to thinking: has anyone made a movie about people making a big-budget science-fiction thriller, and discovering about 2/3 of the way through that the movie was an unsalvageable disaster? Because that would be an interesting movie. Sphere was interesting in this way: its ineptness kept rising to new, increasingly innovative levels.

I kept wondering exactly how it went off the rails, and at what point everyone realized it. Or did they realize? As Dustin Hoffman does his impression of Rain Man in the Marianas Trench, is he thinking, "I'm going to kill my agent"? Or: "Perhaps I will put my new Oscar in the solarium"? All these big-name actors signed on, and they had a big-name director, although one not best known for science-fiction thrillers (Barry Levinson, who maybe wanted to make Diner in the Marianas Trench). It's based on a Michael Crichton novel, which should have meant competently delivered, if sexist, thrills. (They at least got the sexist part down, with Sharon Stone as a scientist unable to perform professionally due to obsessive rage at being jilted by Dustin the Psychologist--who tries to explain her problems to her while their underwater "habitat" is exploding.)

So what happened? Was it a series of little cracks getting magnified successively throughout the production? Did somebody really important storm out midway, a la Dracula? Was the original story OK on paper, but actually, surprisingly, unsuited to film?

Coincidentally, io9 posted a piece today called "Ten Black Sci-fi Characters Who Aren't Turned into Cannon Fodder." It does not mention Sphere--but the film makes a significant contribution in this area. Samuel L. Jackson's mathematician lasts all the way to the end, the third wheel for the reconciled Sharon and Dustin. Mind you, as a reviewer on Netflix pointed out, according to the book, his character technically has to be asleep for most of the movie. The filmmakers gave him a trifle more to do, which suggests they realized a perpetually sleeping black character was a problem in itself. Unfortunately, keeping him awake undermines the whole premise of the movie. As for offing a black character in the first act, though, Sphere comes through by having Queen Latifah stung to death by jellyfish. Which come from Dustin Hoffman's mind. I am not kidding.