I think you need something with some mass and that's moldable so it fits snugly against the door if it's going to do any good. Have you considered making a snake within a snake with the core being sand for mass, and between it and the snake you see, stuffing with wool? Or maybe sawdust?
Invasive plants are Earth's way of insisting we notice her medicines. Stephen Herrod Buhner
Everyone learns what works by learning what doesn't work. Stephen Herrod Buhner
The government thinks you are too stupid to make your own lightbulb choices. But this tiny ad thinks you are smart: