I had this bizarre pet that kept changing size and shape throughout the dream -- consistently referred to it as a "hedgehog", but at one point in the dream it was the size of a cat and the shape of a guinea pig, lying on my lap and sleeping peacefully, but totally bald, since it has somehow retracted its spines(!!) as it slept. When I woke it up, the spines started growing it out again, and I gently moved it into my purse so I could walk somewhere.
Later, I was in a crowded movie theater and the bag started thrashing around, and when I opened it the "hedgehog" RAN out of the bag. Spent the rest of the dream trying to find it in the theater, unsure if someone had stepped on it -- it had changed size to about the size of a mouse, at this point -- or if it just hated me and was avoiding me.