Here it is, the unicycle I’ve spent a good part of the summer hunting for 
My daily scouring of online listings paid off!
It was a local listing about an hour and a half away, so including the price of gas I paid around $70 for it.
One interesting thing I noted during my search for the Squid was there seems to be two variants of it where the saddle and rim differ a bit.
- One variant I’ll dub the Lite version has a 28H rim and a smaller saddle with a metallic finish on the bumpers
- The second variant I’ll call the Plus version has a 36H rim and a bigger saddle more suited for adults with black bumpers
(Both of these are just speculation on my part; it seems like there’s a bit of deviation when it comes to saddle-rim pairing)
I happened to get a Plus version which I think is a nice touch. Although I’m going to swap most of the parts out anyway, it’s kinda neat to have a Mongoose branded unicycle saddle floating around in my parts bin 
(For those curious about the design of the saddle, it’s identical to the generic ones you’d find on no-name Amazon/ebay/etc. unis. Maybe with a better build quality)
Other observations I’ve made after disassembling it for cleaning:
- ~125mm bearing spacing, cotterless
- 22.2mm seat post diameter
- Tire is manufactured by Carioca, no model name. 20x3.0" (76-406)
- 170mm cranks
There seems to be about 1 1/4" of clearance between the top of the tire and the bottom of the seat tube (which oddly continues about 2" below where the legs meet). Which makes me curious if I could fit a 24" wheel in there… I did see a post here where somebody managed to shove a 700c wheel in one of these things with a bit of cutting.
In terms of how it rides, well… It’s quite possibly the worst handling unicycle I’ve ever ridden owing to the combination of a) a short seat post, b) huge cranks, and c) an old, presumably cheap fat tire. But I was expecting that. I wanted to get one of these as a project and throw some nicer parts at it to make it into something worth riding. Even if it is polishing a turd 
So my plan for it is an entirely new wheel set (rim, cranks, tire, hub), longer aluminum seat post, and a better saddle. I was also thinking of getting it powder coated, though I do like the stickers on it… I’d go through with the powder coat if I could perhaps get reproduction stickers to go back on it. I’m envisioning it’ll be a sweet end result 