Been trying to google this one for years to no avail.

Here are things I remember about the movie:

1.) The monster had long arms/tentacles

2.) The protagonists kill it in the end by using some form of gunpowder fuse that they light with a cigarette.  The house it was in explodes, and you hear it wailing as it burns up. I think you even see the tentacles moving around in the flames.

3.) Earlier in the movie a girl falls down into a cavelike basement area.  Her friends above say they will go for help, and while she waits you see the monster emerge from the shadows.  Then I frantically changed the channel, so unfortunately can’t say what happened next.