The design: a normal sofa/ couch with different colours (opening door animation would be the bit of the sofa you sit on opening up)
Why I came up with it: I was sitting on my sofa trying to think of ideas, then as I lost my crisp packet down the side of the sofa I realised, why not have a Tardis that is very comfortable, but all while being hidden.
images: I’m bad at drawing and can’t use blockbench to save my life so here is a picture of a Minecraft sofa