I saw this movie for the first time in 1978. someone decided that the jr high should show movies for the kids on Fridays and this was the first of many promised to be shown. sadly, it was the only movie they did the entire three years I attended Longs Peak Jr High.
I had been wanting to see the movie since reading about it in various mags so of course I was going. they showed a Road Runner cartoon first, which was great as well. then the movie started. I'll admit it, muck monsters scare me. blech! I really enjoyed the movie, but it was creepy at that time. now it's a lot of fun, especially the opening credits.