OK, now pay attention:

There used to be this little thing that went up across the doorway of a house I went to once, but it disappeared. It was made of green or blue plastic that was covered with pips or bumps, pickyerword, and it covered the whole top of the doorway. I never knew how they worked, because I was probably too young, I assume it was something to do with hair dye, and if you walked under it, it made this noise, like poing and it would move, like shaking or something, I don't know, again, it's been a long time.
I visited the house again, and the thing was gone from across the doorway, and the people who lived there didn't remember what it was or what I was talking about, but the thing is, now I need to get one, but I can't for the life of me figure out what it was called.
Anybody got one?