How do cats manage to alter their weight so significantly?

Psycho Cat weighs, at most, about ten pounds. Probably a lot less – I’m cack at gauging weight of things like that. But at the end of the day he’s really not heavy. If I didn’t value my skin/face/arms, I could easily pick him up.

But at night, when he’s asleep on our bed, he seems to gain mass at an extraordinary rate. If he’s flat out, I can’t move the sod without major effort. All of a sudden there’s just this half-ton weight in the middle of the bed, taking up quilt, and it just can’t be moved.

It makes me start wondering if cats aren’t pan-dimensional, and capable of redistributing the weight and black mass of the universe. But only at night, of course.