I was wondering whether funnel webs can live in apartments five levels above the ground? I found what I believe to be one - have cross checked with your description - although it is only around 1cm long. It could have attached itself to my luggage as I returned the day before from airport/taxi. And it did jump out from under a black plastic bag which came out of suitcase. But the bag had been on the floor for around 24 hours.
I am paranoid now as I think it is a young male. What is it doing in my apartment? Could there a big nest of them in my building? Living in the drains? They're dark and moist.