One of the giant spider movies scared the bejeezus out of me as a child. I don’t know the title, maybe just The Spider. There was a scene where a spider leg whipped across the windshield of a convertible, and another where a couple of teenagers were caught in the web (sticky ropes, but well done for the time), and a scene with victims (still alive) in cocoons.
“And to hell it can go!” Ed Naha’s review quoted in The Golden Turkey Awards book, so I did not forget. 
This is the one episode of Space: 1999 that I have always remembered from my childhood. I found it very scary and disturbing at the time (I was seven when it aired.) Apparently, I’m not the only one.
Don’t forget the mummies.
That used to be shown on the Saturday Creature Feature when I was young, more times than I can remember. zzzzzzzzz…There was one b/w movie set in the Everglades, I think, some critter grabbed white trashy women and dragged them to an underwater cave, to eat later. That one disturbed me more than the walking tree with a knife stuck in its face!
I didn’t say it sounded like a good movie.
Conspiracy. They were apparently supposed to be a recurring villain but the Borg got the part instead.
Whoohoo! I get to introduce… Killdozer!
The monster inside all of us.
I don’t know if “shined” is the right word, but they’ve made at least half-a-dozen horror movies featuring a leprechaun.
That was one of my favorite episodes. Jonathan Frakes actually ate a bug in this ep though it never made it to broadcast.
The Lamia from Drag Me To Hell.
+1 on that Space 1999 episode - I was 7, and it was the fuel of nightmares for quite some time.
I’ll nominate the Cenobites from Hellraiser, AND that monster in the hallway that we get a glimpse of going after the girl.
The Day of the Triffids, monsters that could only be stopped by
Salt waterThen there were The Monolith Monsters, who (coincidentally) could only be stopped by
Salt waterI sense a theme here. Why would any monster want to come to Earth, where 70% of the globe is covered with instant death?
Roddy
Quetzalcoatl from Q
***The Invisible Man
Jurassic Park***
From Hell… I saw that when it first came out in the fifties. Even as an idiot child, I laughed at unbelievably ridiculous that monster tree was.
Another one from the same era: The Giant Claw about a giant buzzard. You have to see this monster to believe it. Apparently, it was not intentionally hilarious.
Attack Of The Giant Leeches.
Well, it’s very rapid death to us, too. (Drop a man into the North Atlantic, stark naked, and see how long he lasts.) So, too, is the vacuum of space death to us, and probably to most alien invaders as well. The answer is the same in all cases: tool use. Presumably, our alien invaders believe they can craft sufficient protection from our hostile environment, and do it cheaply enough for invasion to be worthwhile. They always turn out to be wrong, but it’s not obviously silly to make that decision.
The sea monsters in Deep Rising, an underrated action/horror flick.
Technically, that was only one monster in Deep Rising.
How about ** The Wonky**?
or that turnip-alien from It Conquered the World?