The largest domestic breeds push up to 300 to 400 kilos. We had one free-range pig on our farm that was certainly over a quarter-tonne, and she was agile enough that she'd occasionally run down chickens and eat them, and jaws strong enough to chew up cow skulls left over from home-kill.
Pigs are generally smart and friendly if they haven't been mistreated. I would not want to mess with one.