ToME: the Tales of Maj'Eyal

I was in Rak'Shor level 1, had cleared most of it, and faced an eternal bone giant in one of the internal buildings/rooms. As a cornac summoner, I summoned a red dragon on top of the bone giant. As soon as the dragons appeared, all characters on the screen disappeared, my own character included, and days started passing in about 1 second each. The light level waxed and waned quickly, and I could access all the non-character features, like the escape menu, the dialogue screen, etc, but I couldn't move my (invisible) character or use talents. My HP didn't regenerate at all, either. I closed the game with Ctrl-Alt-Del.

You got no error message at all ???

I have also hit this bug. It seemed to happen after a master archer shot me with something, perhaps. The character disappeared, days passed every few seconds, but I couldn't move or make any actions. I could use the rod of recall, but it's stuck at 41 turns, and so never actually activates. Saving and loading doesn't fix this, and unfortunately clears the log so I can't read exactly what happened up to the event.