They're buggers of things, they pop up next to ya when you don't expect it.
A few years ago, I was driving back to Armidale from Sydney (about a six hour drive), I was in my work van which never gets cleaned and there's tools and bits of wood and candy wrappers and empty coke bottles all over the inside of it.
It was night time and all of a sudden this huge tarantula cam out of nowhere and ran across my windscreen. So I put the windscreen wipers on, and then realised that the spider was on the inside of the windscreen....hee hee.

I wound down the window, and tried to flick the spider out of the window with the back of my hand (all of this was happening whilst I was driving at like 100kph). Anyway, the spider jumped onto my right forearm, and in my panic I opened the car door and flicked with my whole arm out the door. So then I pulled up, found a workable torch amongst the detritus in my van, and did a thorough search.....no spider.
I resumed my journey.
The next morning I went out to the van to get some stuff, and there was the spider.....not dead yet....but squirming on the drivers seat.
I figured he must have run up my arm so quickly and down my back, and I'd sat on him for a few hours....hee hee.