Here is a quick look at an eight foot tall backpack style costume I made for my son this Halloween.The school would not allow him to walk on stilts on campus so I thunk around the issue by using a PVC backpack mechanism design I originally created in 2000 for a giant dragon costume that scared the Bajeezus out of the neighborhood kids.
This characters name is Slenderman.
With some PVC pipe, gloves, spray foam, pipe insulation, electrical tape, wig head, pants, shirt, tie, jacket, spray glue, spray paint, eye of newt and spare CPU cycles SLENDERMAN IS ALIVE!.
dry fit everything without glue, scale the size according to the shirts and pants and suit performer you have chosen respecting the padding encroachment. I had to cut Slenderman a little short so he would not scrape his head on the ceiling. the arms totally dangle down reaching for someone when you lean over toward them, with a little additional work you could "rod puppeteer" the arms. additional arm tentacles could be servo driven and added to the backpack mechanism. a 3 axis servo platform could animate the head movements.
measure thrice, cut twice, dry fit, adjust, test, rinse, repeat then glue weld, solder, tig, bead, braze, crimp, mind meld...etc
for more information on Slenderman, The slender man, or Slender Man see en.wikipedia.org/wiki/Slender_Man
AJD 2013