i remember a long time ago i used to watch this anime on TV its about a boy with a alien?
Description of the Alien: the alien can change into different things, like one time a scooter that can go either really fast or really slow -the alien im pretty sure has like spikes on his head -he is like blueish-green
one episode shows this guy trapped in time, with bunch of stairs, another episode shows them "wearing other people" as in you're wearing someone els skin, and they were taking them off, zipper on the back
I cant remember anything like that buy maybe more info would help, like... is the alien anthromorphic or like an animal? Is it horror? comedy? And what do you mean by "them"? the boy and the alien or are there several aliens?
I remember that! I think...it definately rings bells...did the kid have a large mixed gender group of friends?
Also what country was it aired in (which country did you watch it on tv in), about what time period and if you have an idea of the channel that would also be useful. Even if you don't specifically know the channel there were likely a few channels you frequently watched so if you narrow it down there's a higher chance of finding it.