It was a Norwegian Forest Cat. She looked a bit like this one:
She was pretty wild; left me at least one scar, half an inch long, between right collar bone and the neck. Little devil. She would creep behind a corner and jump out and attack the unfortunate person coming out from the room. Sometimes she went into frenzy and ran around like mice heading for a hole. Across the flat she speeded and back again.
But then it turned out my brother was allergic to many things, cats included, and she left to my dad's place, a few hundred kilometres away. She has caught a few birds ever since, so I guess moving wasn't all that bad for her.