Cardboard minis work well if you back them with a vinyl floor tile. They’re self adhesive, less than $0.50 a square foot, and you get a pile of rugged minis. You can buy individual tiles at hardware stores.
I wanted my group to be motivated to stop the savage tide from spreading. Specifically, I wanted them to feel like the shadow pearls were somehow their fault. One party member lived in Shadowshore, and he was contacted by a gray market trader of oddities. Said he learned of a hidden chamber on Dead Man’s Roost, a rocky island 30 miles from town. Dead Man’s Roost was covered in ruins that were thought to have been picked clean years ago. Anyway, the trader gave them directions to the entrance of the chamber, key words to locate and open the exterior door, wax for the party’s ears (because the wail of the chamber guardians will kill you or drive you mad), and vials of acid to pour on the protective glyphs on the inner door (without looking at them, or you’ll get fried). Under the inner door was supposed to be a shaft to a small library, and the party was to bring back a book and keep whatever else they found.
They went to the island, plugged their ears, opened the outer door, backed up to the inner door, poured acid on the glyphs, opened the inner door (shaped like a man-hole cover), and out streamed a cloud of tiny black skulls and an awful smell. They all failed their fort saves, became nauseated, and now have arcane marks of a demonic symbol on their foreheads. There was no shaft, just a lead lined semi-spherical chamber under the cover, lined with magic glyphs of containment.
At this point, the party got suspicious, took out the wax, and heard a pleasant voice repeating “Danger! Do not enter. This is a containment area.” They looked at the back of the lid, and saw the mirror image of what was (formerly) on the top surface. Once translated, it said “Containment chamber number seven.”
I added tiny black skulls to Harliss Javell’s description of the shadow pearl exploding.
I’m hoping I can tie this together later . . .