As always, many SPOILERS here.
23. Clash of the Titans (1981)
We begin with Calibos himself, who was cursed by Zeus for hunting down his sacred winged horses, leaving only Pegasus. Then there's the giant vulture that carries Andromeda's spirit about the swamp, the Stigian Witches who share one eye between them as they cook someone in their bubbling caldron, and a two headed dog nominally guarding the gorgon Medusa. Medusa is of course a monster mix on her own, as she has writhing snakes for hair. After Perseus nabs her head, there are some giant scorpions to defeat (along with Calibos) and then they have to take care of the Kraken itself. Not bad for a monster mix.
It isn't even a little scary (although the scenes with Medusa have a reasonable creep factor), but the animation is great fun, and the monsters have some fine personality. So put this movie in your Halloween rotation as a good creature feature!
24. Heavy Metal (1981)
The plot here is exceptionally loose. A framing device was used to tie together mini-stories that otherwise have no relationship to one another. The only commonality is the malevolent green orb known as the Loc-Nar. This orb narrates its past conquests to a terrified girl, and each of these becomes a vignette in the film. Having already melted her astronaut father to mush, the orb recounts stories such as how it converted plane-loads of soldiers into zombies, created war on several planets, and influenced people to act in malicious and evil ways. Most stories are populated with a variety of monsters and weird alien creatures that keep things interesting even when the plot flags.
It is the utter unknown that makes this movie so unsettling, as you can't even guess what's going to happen next, and it's usually something violent or otherwise unpleasant. Animation lets you do pretty much anything you want, and in this case it runs wild. So break out this old flick and see if its weird worlds and creepy creatures are what you need for a bit of Halloweeny viewing.
25. Lord of the Rings, The Return of the King (2003)
So the first film has goblins, a cave troll, and then a demon known as a Balrog. This in addition to the usual orcs, the quasi-monster Gollum, and then of course the terrifying Nazgul that are in all the films. But the third movie has a few extra special monster encounters. We start by learning Gollum's story - a once normal hobbit-ish person who was corrupted and cursed by the Ring to murder his only friend. Then we end the film with Gollum's demise, a twisted moment of glee before the flames of Mount Doom take him as well as the Ring. In the meantime, Aragorn has to obtain the help of the Dead Men of Dunharrow, ghost-skeletons of men who betrayed Aragon's ancestor Isildur, and who have been haunting the countryside for centuries. Then there is an up close battle with the Witch-King, leader of the Nazgul, whom Eowyn finally dispatches.
Finally, and what really makes the most monstery list for me, is the encounter that Frodo and Sam have with the giant spider Shelob. This is a freakish and terrifying sequence, where Frodo finds himself lost in the webs, and only survives because loyal Sam shows up at just the right moment. It's all quite gruesome and gross, which makes it perfect for a Halloween creature feature. So depending on the amount of time you have for seasonal movie viewing (the extended versions of the trilogy add up to like 13 hours of film) put one or all of these fine monster movies on your list.
Image Credits: https://commons.wikimedia.org/wiki/File:Rubens_Medusa.jpeg https://www.rottentomatoes.com/m/clash_of_the_titans/pictures/#&gid=1&pid=n-241117 https://www.rottentomatoes.com/m/the_lord_of_the_rings_the_return_of_the_king/pictures/#&gid=1&pid=h-6597