Halloween's terrifying turnips

I would just like to remind the world that Halloween is an Irish tradition (and also Scotland/Wales - basically Celtic) There were no pumpkins in that part of the world and in fact it was traditional to carve a jack-o-lantern from a turnip, like the one in the photo here, which would eat and shit out any of these cutesy orange pumpkins I keep seeing all over the place.

That photo is from Wikipedia's Halloween page which says it's from the Museum of Country Life. Who's up for a bit turnip carving this Halloween? I don't know where to get one in Japan.