I grabbed nine large black plastic garbage bags, a roll of black electrical tape (I always have a blade with me) and carried them out to a huge pile of leaves as a project I could do with the kids.
I filled one bag loosely and sealed it up with tape, then roughly divided it into one fourth and three fourth parts. I wrapped the tape around the division and set it aside.
I split the eight remaining bags along both sides, unfolded them, re-rolled them side-ways into very long bags, not so large in diameter, re-sealed them along the sides with plenty of tape and then loosely packed them with leaves. I put a few sticks lengthwise (to help them stand up) into the eight long bags, divided them using tape into roughly one half, one third, one sixth to make legs and assembled them with the big bag I had set aside into one GIANT BLACK SPIDER, which now sits waiting for trick-or-treaters in my front yard.
I added curved sticks for fangs, white rocks for eyes, a few streaks of red (on the fangs and eyes) and brown (to create texture) paint and we have something like a "leafman" (instead of snowman) Scare-Spider (instead of scarecrow) lurking hungrily, waiting for kids to walk by on Halloween night.
Seasonal decorating is very much out of character for me, but I really enjoyed doing this with/for the kids.