Heh...this one happened to me...
Take an old lawn chair or something, on the front porch (or by the front door). Dress up in way old clothes. Stuff your clothes with leaves, etc...looking like a scarecrow or something. Put a pumpkin (fake or real, whatever
over your face, hat on top. Seriously, like a scarecrow.
Just sit there, don't move.
Kids come by with their parents...the parents will probably ignore you. When the kids look..jink your hand up.
Kids will probably pull on mommy/daddy's pant leg and say you moved. Be still. It'll pass.
Do it again when the parents aren't looking.
Continue on this until the kids get to go.
When they all leave...and the kids turn around to look at the mysterious moving scarecrow...
Get up and wave goodbye.
Then sit back down and go still.
SCARED THE SHIT OUT OF ME when I was a kid.
Sure it'd work today, too