Used for the "simulated train whistle" in the outro of "Dreaming Number Eleven", as stated by Satriani in the April 1989 Musician interview "The Devil And Joe Satriani" by Ted Drozdowski. In Strange Beautiful Music: A Musical Memoir (2014), Satriani recounts that it was his first effect pedal.

Musician, April 1989, “The Devil and Joe Satriani” by Ted Drozdowski

MUSICIAN: So the band first played about a year before the live songs on your new EP were recorded in June '88 at the California Theater in San Diego. Where did the title Dreaming #11 come from?

SATRIANI: It was actually the title of a song on my first EP. It was just one of those funny little phrases, like Surfing with the Alien, that pop into my head. I applied the title to a song on that EP that was a strange collection of sounds. It had an Allen wrench on the pick-ups for a kickdrum, slowed-down scratch for a snare, a sped-up tapping on the strings for a closed high-hat sound. I had all these percussion sounds generated just from a guitar plugged directly into the board. And on top of it I had bass, but it was actually a guitar, not even detuned, just playing popping bass. Then I had a rhythm guitar that sounded like an outgrowth of James Brown, but in retrospect it sounds more like what Prince got into with 'Kiss' and 'Sign o' the Times' and 'Alphabet Street' – that sort of dry guitar set-up. And I had this R&B guitar melody over it. The song ended in a simulated train whistle that I did with a Big Muff and a weird technique of pulling strings over other strings and then off the neck. That song was a collection of non sequiturs, and I thought 'The Crush of Love' and the three live songs on the new record didn't really have anything to do with each other. So Dreaming #11 applied.

Strange Beautiful Music: A Musical Memoir (2014)

Chapter 1, pg. 8

My first effects pedal was an Electro-Harmonix Big Muff Pie [sic] fuzz box that I bought through the mail after seeing an advertisement in Circus magazine, and it was the biggest, fattest fuzz ever created. This was the first of many pedals to come.

It was very confusing when I first played with these pedals because I had no idea how to use them, or how to make myself sound like Hendrix! There was no YouTube back then to instantly instruct you how to set things up, or on what sounds you could get out of a new piece of gear—you were pretty much on your own. After starting with the Big Muff, the next thing I got was a Maestro Phaser unit with the three buttons on it, and then the MXR, another phaser unit, and then a wah-wah pedal showed up eventually. I really didn’t have a whole bunch of pedal back then.

Chapter 5, pg. 50

On different moments on that record, I definitely needed distortion, and I think I had my original Big Muff Pi by Electro-Harmonix, which was still working at the time, and DS-1 and OD-1 pedals.

In this photo, you can see a few of Chris's many pedals. Though he's mainly used a Black Russian Big Muff Pi since the early 2000s, a regular Big Muff Pi can be seen here on his Drones-era board.

In this Facebook photo, we can see that Tom owns Electro-Harmonix Big Muff Pi in his studio.

Jamie Cook used the Electro-Harmonix Big Muff Pi fuzz pedal during the recording of their first album. The use is evidenced by a user-uploaded photo.

In the Premier Guitar article "Dot Hacker: Psychic Friends Network," Josh Klinghoffer is noted for using the Electro-Harmonix Big Muff Pi fuzz pedal.

According to rig diagram by Guitar Geek, he used two Big Muffs : one old, and one new.

In this Instagram reel https://www.instagram.com/reel/B3NMY0tDMvQ/ you can see Frank playing Bulletproof Heart with the caption reading "yknow it’s funny, triggers be damned... it’s been 9 years and counting and still whenever i click on an old Big Muff i just have to play this song 🤷‍♀️"

In this YouTube filmed on September 21, 2011 at the Culture Room in Ft. Lauderdale, FL. The Big Muff can be seen next to the two Line 6 pedals.

Used live for the "The Anarchist" solo, as listed in this October 8, 2012 Premier Guitar interview.

Effects

Electro-Harmonix Big Muff (for “The Anarchist” solo), MXR Flanger, MXR analog delay, Boss Flanger, Electro-Harmonix Memory Man, Boss Compressor Three Fractal Audio Axe-Fx IIs, TC Electronic 1210 Spatial Expander + Stereo Chorus/Flanger, two Apple 2.6 GHz MacBook Pros running Apple MainStage UAD plug-ins and Native Instruments Guitar Rig 5, two Universal Audio Apollo QUAD audio interfaces, Jim Dunlop Cry Baby Rack Module wah

Used on The Blue Album and Pinkerton, according to the following sources. The version is not specified in either.

Guitar World, March 1997, "Schoolhouse Rock" (as transcribed on Weezerpedia)

GW: Pinkerton, however, is gimmick-free.

Rivers: Yeah, we trimmed that part of ourselves—it was the natural thing to do. So I think we're also going to trim some of our audience, which is unfortunate. We were never one of the top bands like Green Day or Offspring anyway; we were always a notch below. Maybe now even two notches below. Yeah it's a bummer, but I don't really feel like I have a choice in the matter. I've got to do what I've got to do, and right now that means not making the gimmicky video and not using language that's quirky. It means speaking more directly. Maybe the audience will be smaller, but at least they'll be liking us for the right reasons.

GW: What guitars and amps did you use in making the record?

Rivers: I think I used Gibson Les Pauls. I don't remember whose they were, where they came from, what kind of specifications they had—but I know they were Gibsons. For amps I used Marshalls. I also used a Big Muff quite a bit. It was about as standard a setup as you could have.

Chris Shaw, Gearslutz, "Weezer Say It Aint So Chorus Vocal Sound", Comment #34

Ummm, Some corrections re: the Blue Album:

• Vocals were done with a U67 at Electric Lady and a U87 at Rics house (surf wax, and some bgvs)
• There were NO REVERBS OR DELAYS at all on the record (The sole exception being a long delay used to extend one of the feedback parts on Only in Dreams). Ocasionally I used a stereo delay from the Lexicon 300 to delay the room mics slightly to get a little more slap. The band used to come into the control room at the start of the day and turn off all of the delay / reverb based outboard gear.
• When we did the recall for the Say it In't So single the assistant on the session called me while he was recalling the mix because he thought we were missing a few pages of notes. The only piece outboard was an 1176 on the ld vocal. That's all I used. Everything else was just the SSL E.
• All BGVs were doubled or tripled - no obvious artificial chorus was used at all. The only effect I might have used would be an Eventide 910 set to 15ms on the left and 7.5 ms on the right. (harmonize ratio set to 1.00 (that thing always drifted slightly anyway). This was only used to widen the lead vocal in a very, very, very subtle way.
• The album was tracked on Electric Lady's Focurite Forte console in Studio A with the remote pres (the pres were in the live room and ran at line level to the console)(I posted some pics around here of it.). Some overdubs were done on the SSL G in studio C (I distinctly remember cutting the gtrs for in the Garage up there. I believe we used a Tele through a Big Muff using E. Lady's Fender Twin for that tone. We also cut the clean rhythm for Say it Ain't So up there on Ric's Jaguar using E. Lady's Fender Twin
• The bass break for In the Garage was my Electro Harmonix Graphic Fuzz (original, circa 1980) across the insert on the SSL.

Used on early TMV pedalboards

At 0:16, you could see the big muff on his pedalboard.