When making up fantastical and magical creatures in your campaigns, what kind of design philosophies (difficulty...

When making up fantastical and magical creatures in your campaigns, what kind of design philosophies (difficulty, weaknesses, powers, behavior, gimmicks, appearance etc) do you usually work with?

>Be interesting
>Serve a purpose
That's it.

>be interesting
it has tentacles instead of eyes. the interesting thing is, the tentacles ARE the monster.
>serve a purpose
to cause, under all circumstances, a TPK

something like that, right?

>Nature is scary.

>Have more herbivores than carnivores, hippos show that they can be just as agressive.

>Oceans are so huge you can hide lots of giant monsters like in real life.

>Prefer unique creatures instead of a species.

>Some can metabolize magic.

This

I usually focus on weaknesses, resistances, and interesting abilities. I like it when the party has to puzzle out what works and what doesn't on a monster.

A current idea I had was for some sort of fire aligned creature that could bless nearby weapons into doing fire damage.

So in a fight it would use that to buff any allies, but also on the PCs so they could resist their weapons.

>enemy enchants his opponent's weapons in a way that they heal him

Honestly I usually just hybridise Monster Hunter creatures

I had a puzzle-ish type monster kind of like that. It was basically a floating ball of magic that had two modes, blue and red, that it switched between. When it was in blue mode, it absorbed all the heat around it to deal cold damage and fire attacks healed it. Once it absorbed enough heat (fire damage taken + cold damage dealt) it switched to red mode. In red mode it vented heat to deal fire damage and was healed by cold damage, switching back to blue once it lost all its heat.

So the 'best' way to kill it was to hit it with the same type of damage it was dealing at the time, fire when red and cold when blue.

My hopeless addiction to world-building forces me to ensure that my creatures either fit into an ecosystem, or are the result of some recent magical fuckery.
SudsDuck
A magically altered species of waterfowl which has bred in the wild. Inhabiting wetlands and swamps, they primarily feed upon invertebrates and water-plants. These birds are named for their strange response to threats from predators. When facing attack, Sudsducks spit an irritating solution similar in makeup to bubble soap. Like spitting cobras, they commonly aim for the eyes of an attacker. When building their nests in the spring, sudsducks coat their nests and eggs in this solution in order to make them distasteful to predators.

Whatever I saw in a nightmare.

Creatures tend to be more interesting if you think about how they go about doing what life does: propagate as much as physically possible without starving yourself out in the long term. It helps if magic comes with a cost or requirement that makes it implausible for heavy use by nature.

The Fire Dragon has no wings, but it flies. This is because the fire dragon has float bladders filled with hydrogen. If you light a fire dragon on fire, it will explode! Especially since its breath weapon is also a non-magical cross between gasoline and napalm. The onlh magic it uses is the low-cost strengthening magic that allows it to grow to its prodigious size, and possibly an ounce of air magic to help the hydrogen along.

The Unicorn is 100% non-magical. It uses its horn as a self-defense tool and mating attractor. Male Unicorns tend to joust in glades over herds of females. They pull aside so as to not kill one another though.

Wyverns have stingers on their tails that are filled with the most lethal poison known to man. They also hive in groups of more than 100. Why? Because they exclusively eat dragons, of course!

When you see a creature in the monster manual, think about what would eat it. Or rather, what is the most efficient, non-magical way to kill and eat this monster.

Good monsters don't just fight the party. Good monsters are constantly reading dungeon meshi for tips on their next meal, the party is just prey/a intruder on their territory/a possible predator/covered in neato shiny shit that might get them laid/stepping on the ironwood tree saplings they've been cultivating with dragon dung.

Thinking like this is how you make your PCs scared of Dire Aphids.

Sounds to me like the solution is to hit it with weapons until it breaks.
Why even use those very particular elements on it?

I didn't mention it, but it takes extra damage from the proper element and has a degree of resistance to normal damage in order to make it an actual challenge beyond the minor puzzle aspect. It primarily uses AoE attacks, and is an earlier game enemy encountered before resistance to its two forms of attack is ubiquitous.

You can definitely kill it by smacking it with weapons, but it's far easier to do once you figure out the "trick." It's intended to be encountered only one or two times after the initial encounter, and never again after the novelty of instantly demolishing a formerly threatening enemy wears off.

Basically a one-time use "hey, some enemies won't have totally obvious weakpoints" primer.

Depends a lot on what the artist gives back to me. Generally, though, I aim for a bit of differentiation from humans, often via minor magical adaptations. Behaviorally, I look at the brain and what areas control what parts of human behavior, then turn one up and turn another one down.

It's gotta make my peepee hard.

Now I want a small pet cube for my PC that jumps around like that..

>be concise and quick as coldsteel
>don't actually contribute to conversation
Nice try

A dragon with telekinesis.

Sometimes I build around an interesting tactical ability. Especially for groups of monsters or things that will have to be the base for a lot of monsters (beefolk, beefolk cleric, beefolk berserker, etc because apparently we're robbing a beefolk hive). 4E actually has a ton of good designs for these, I'm not above digging through it for more. Also I overuse pulling attacks so there end up being a lot of frog-like creatures via this approach.

Other times I try to shoehorn a normal mythological creature into making some sort of ecological sense, and grab everything else that comes with it. Like, hydras definitely are river monsters, and they use all those heads to check under rocks for hellgrammites the size of your arm. So now we know there are giant dobsonflies, that's worth at least a jump scare.

But the biggest thing, I think, is just putting monsters into some sort of context. Why are there a handful of desperate goblins ambushing us in this abandoned dwarven village? Who left that awful frankendragon here and why? What is that manticore living off of down here? You can use some pretty generic monsters and make them interesting if you get your players are thinking about where they came from.

that's probably the amount of creativity expected from

Dunno if it counts as a "creature", but I once had a holy town built over a massive collective of magic fungus. It'd eventually become known as holy fungus after its discovery, but it was created by a chaotic evil mycologist to be a sort of battery for evil magic by absorbing and metabolising magic as a food source. In his laboratory, there was more evil than good magic, so the fungus began to eat more and more evil magic. Eventually some spores escaped, and as magic is everywhere, they spread and spread. That was a few thousand years ago, so some form of it is pretty much everywhere.

Explorers would find a plot of land where evil magic was particularly weak, and so they'd assume it was holy land and build a city over it, but it was just the fungus underground.
It can be harvested and used to power magic stuff, but it's usually pretty hard to actually get to.

I've used it to handwave why certain magics are more common in certain places, or why certain areas hold almost exclusively lawful good or chaotic evil races [the fungus feeds off their energy], and one colony of it once gave off a low level telepathic field, which made people think it was an act of God even more.

>metabolize magic
What happens when they shit

>What happens when they shit
Shit happens

Seriously though, the don't metabolize it through digestion, although you gave me food for thought about the void-lamprey which parasites whales bigger on the inside than the outside and sucks sheer space.