Deflated Rastafarian hedgehog

A description from Terry Pratchett's Hogfather:

Death, pillow slipping gently under his red robe, stood in the middle of the nursery carpet...

It was an old one. Things ended up in the nursery when they had seen a complete tour of duty in the rest of the house. Long ago, someone had made it by carefully knotting long bits of brightly colored rag into a sacking base, giving it the look of a deflated Rastafarian hedgehog. Things lived among the rags. There were old rusks, bits of toy, buckets of dust. It had seen life. It may even have evolved some.

Now the occasional lump of grubby melting snow dropped onto it.

Death has (I think) just crashed into his adoptive granddaughter's life through the chimney of the nursery where she works as a nanny (?). He's trailing some snow from the rooftop.

The line about the hedgehog is a good sentence, and I don't understand it. The vibe of this sentence works well. It's funny and evocative. At the same time, I have no idea what it looks like. What's a sacking base? I searched, but the Internet isn't helping.