Old plastic juice bottles?

Ok, I don't know why I was thinking about this but it's driving me crazy. When I was little my parents used to get this juice jugs they were plastic and kind of shaped like a slinky, you could put it up and make it bigger or push it down and make it smaller....for the last couple days its been bugging me just trying to figure out the name of it....lol...i'm crazy I know....but can someone help me?? I never give up when I am trying to think of something!