We filled recycled glass jars with spiders, cotton ghosts, moss and branches to make Halloween terrariums. This is a great project to make with kids; they can fill their jars with a variety of scary trinkets and toys. Depending on the age of the children, you may want to use regular craft glue instead of a hot-glue gun.
Cut small bat shapes or silhouettes of witches or other spooky shapes from cardboard and paint black, let dry. Or find the shapes on the internet and print out.
Adhere a branch or two in the middle of the moss with hot glue. You may have to hold it in place for a minute or two. Then use thread to hang a spider — or spiders — off the branches, or you can glue spiders to the base of the branch. Add a bit of the cotton spider webbing to a couple of the twig branches.
When your designs are complete, carefully place the jar over the top of the lid making sure not to move the pieces.