Child Stabbed With Spear/Harpoon

[rianmiller]

I'm trying to help a friend identify a movie that he hasn't seen since the late 80's. Any help would be appreciated. I know it's not much, but here's all we know:
 
- A child is sitting on a grate or vent of some kind and is stabbed from below by a harpoon or spear of some sort.
 
- The child may or may not be wearing a bumblebee costume.
 
- The film may also involve a house, the inside of which resembles or has turned into a forest.
 
I know this is a long shot, but we've been searching for this movie for a long time and have come up empty handed.
 
Thanks for giving this a look.
 
- R.

[staircars]

The house which has turned into a forest sounds like it could be Troll (1986). Characters get 'stabbed'' with a ring, rather than a harpoon/spear.

[Rayo Casablanca]

A real long shot but perhaps your friend is remembering the ending of PHENOMENA (85) (AKA CREEPERS). http://www.imdb.com/title/tt0087909/?ref_=nv_sr_2

Here's why it might fit (SPOILERS follow for those who've never seen it):

one of the film's "killers" is revealed to be a boy with severe facial birth defects. He attacks the heroine with a harpoon/boat hook. Maybe your friend conflated it all together with various other things. Happens a lot.