and I didn’t even take a picture of it on the back of the tow truck. I didn’t want to – I’d rather remember this:

After two years of profanity-laced repair work, the cause of death was the natural progression of this injury:

The teeth on the sprocket broke off. The sprocket is welded to the axle. I don’t have the equipment for that level of metalwork, nor am I particularly inclined to pay someone for that. And finding a replacement on a 20 yr old mower is needle/haystack stuff.
It is a sad thing, but it is A Thing. After a moment of silence, I’ll begin the search for a new mower.