what is this insect?

im really intrigued about it since i first noticed it like 10 years ago +-
i think it only appeared in two of the apartments i've been till now(don't know why)
first i thought it was dirt or part of the wall paint, but then it started moving,
it walks on the ground or climb on walls, its a bit slow,got no legs(i can see)but sticks to the wall and sometimes hangs like a spider on a silk filament,its got a head( that helps him move, i think) and something similair on its rear.
well what is it?is that its final form or will it develop to something else (like a cocoon.)
thnaks.
how do i post picture here?
here a link:
http://postimg.org/image/q9wc1myc3/
in the picture you can see only the 'head' but as i said it sticks out its 'tail' sometimes'.