Right so the Christmas level takes advantage of something I built in called level scaling. I can up the stats (and size) of creatures just with a single numerical value, however it wont change things like "CanBePickedUp".
My guess is this is actually a small harvestman scaled up. You will notice creatures not of there normal size all over the Christmas level (and later in freeplay games).
NOW in freeplay creatures use a separate set of rules to determine if they attack another creature (called the avoid list). Almost all creatures are on the funnel webs avoid list, this however will not apply to other areas of the game.
So the question is should the small Harvestmen be able to be picked up in general? For example should a mantis or large beach wolf spider be able to eat it?