As of 11:30 Friday night, the gargantuan turd was still there, and the toilet was still valiantly flushing away, all in vain. I tried to get Mr. Kuus to come in and look and be a second witness to its magnificence, but he declined, saying (a direct quote) "You get weirder every year."
This morning, it was gone. My hypothesis is that all the water churning finally eroded it enough to flush. That's just speculation, though.