the itsy bitsy spider

my window is open (i love this weather) and i have those kind that pull in from the top. this itsy bitsy spider falls down from where my window is open at the top and just hangs there. then he crawls back up his invisible string to the window base. then he falls again, and climbs up again. he does this over & over. i'm wondering - is it on purpose? is it some kind of workout? is he going to sneak onto my desk later today & scare me? LOL