I've never met anyone as dumb as Mushy online, and offline, it's a tough call, when compared with some of the brain-damaged street people I've come to know and love over the years.
There was one crazy lady, known as Stella, who would come up to people at random and start screaming at them, continuing some argument she'd been having in her own head, or in the distant past. A couple of times she was locked up, for scaring the civilians, but they always ended up releasing her, and she'd be back on the streets a few days later, a little cleaner and better-dressed, but just as barking mad. Turns out, her relatives included a Detroit family of some prominence, and they had decided she was happier on the street than in captivity. Eventually, she died of old age, or exposure, some natural cause like that.
Stella was a better conversation partner than Mushy.