Anyone remember this 80s (?) film?

[SwanShaped]

When I was a child, in the 80s, I watched a film about some children (poss brother and sister) who didn’t clean their bedroom. And all the mess turned into a monster under the bed. Maybe involving a black bin liner? And the monster dragging them under the bed. It was a kids film but I remember it being really scary. I’ve googled it but can’t find any reference to it. Anyone remember it?

Anyone?

Under the Bed 1

under the bed 2

Quick google came up with these. I suspect it was the first film.

It was that! I’d forgotten the bin liners bit was that she was wearing it and the monster thought she was rubbish. Thanks!!

Apparently it was written by Bill Oddie and supposed to be a comedy! I remember it being really scary.