All the monsters--P.
I feel like there should occasionaly be a pegasus or at least the rumor, possibility, or threat of a pegasus. However, someone riding a pegasus is a dicey proposition. It's like biting the head off a bat--that's somebody else's bit you're doing and--one way or another--it hasn't made it into Open Style Content. I feel you'd have to make it real weird to make it work again.
The subtext of the modern conception--especially in a DnD context--of the pegasus is a unicorn. You can talk about a unicorn and maybe not remind someone of a pegasus but it's hard not to do vice versa. The unicorn is a clearer construct--it symbolizes purity and untamability.
It seems to me a pegasus should be a much wilder beast. Its mother was, after all, Medusa. The idea of being bit by a unicorn is stupid--I can very easily imagine a pegasus biting someone.
"...likely the result of the same sort of experimentation as brought about the owlbear." Would that be experimentation with an x-acto knife, a hot glue gun, and a bag of plastic woodland creatures?
Not quite, the peryton originated either with Borges or with a medieval manuscript he refers to in his Book of Imaginary Beings and, consequently, is way creepier than its fellow mash-up monster. The stag's head adds not only crypto-satanic associations to the bird of prey but also useful weaponry, while the owlbear is just a bear that can see you real well--which, frankly, never seemed to be something bears needed to work on.
Plus, whoever invented the peryton tried so much harder--there's the tearing out human hearts thing, the enslaving people thing, and the fact that it has the shadow of a person.
Further peryton lore from Borges: the peryton is allegedly only allowed to kill one person and then it can kill no more. When it does, its shadow will match its body again. Also the species was apparently "instrumental in the fall of Rome".
Should I just make fun of the piercer or should I make fun of what the girls would think if I told them that they suddenly saw a piercer or should I realize that life is short and move on to the Pike, giant?
What I wanna know is why whoever invented the swordfish and the flail snail didn't bother to invent a pikepike.
I just now noticed that there's no entry for "fairy" in the Monster Manual or the Monster Manual 2 or the Fiend Folio. Instead we get pixie and sprite (and maybe slyph if you wanna stretch the synonym sprawl a little further). The Manual produces no significant conceptual differences between the pixie and the sprite--they seem to have the same taste in shoes, headgear and weaponry.
So anyway, we might as well talk about the fair folk now. Like elves, they're a little aristocratic and--like elves--it's implied that there's something natural about their aristocracy. On the other hand, they are much more like children and do not necessarily have the grave Tolkien-esque austerity sometimes associated with elves.
Are these just metaphors for the children of the rich as seen by the hardworking people paid to keep an eye on them? Playful, mischevious, demanding, possessed of strange powers, obedient to mysterious but inflexible rules, not all bad but likewise ignorant or bemused by human morality.
These creatures, these sort of assistant gods, were used by mothers to keep their own children in line. "Don't do this or the blue fairies will get you and take you away." If we imagine the standard Christian threat ("Do right or a half naked Jewish king will send you to Hell.") sort of Bowdlerized for the consumption of Victorian children--here's the threat, the fairy folk.
Of course, long before they were scaring children and floating around in lacy dresses they were nature spirits. The implication is not that nature is hostile to us or that nature is our friend but merely that it has a life and a morality that does not intersect our own and which does not acknowledge our own. It is, in its way, a very wise philosophy.
The Renaissance-thru-Victorian idea of fairies is interesting in this way--my off-the-cuff impression is society had passed the point where these nature spirits were considered essential you-must-propitiate-them-if-you-want-shit-done envirospiritual bureaucrats but hadn't yet reached the point where everyone knew they were bullshit. Therefore they were just different than us. They had a parallel world that did not necessarily intersect ours.
I don't feel as though the fairy folk really should have to have any well-defined ideas about people. An adventure involving fairies should be about culture shock on both sides. Your armor and your magic should seem as ridiculous to them as their shoes do to you.
I have never seen any uncute photo of a porcupine. While I'm sure that many of you have harrowing tales of porcupine quills, I'm just not going for it. I feel the girls would probably refuse to fight it on general principal anyway.
Portugese Man-O-War, giant
There's no Jellyfish, Giant in the Manual but there is the Portugese Man-O-War, Giant. So I'll use this as a catch-all for all the variations of jellyfish monster.
I think there's no reason that jellyfish monsters shouldn't be intelligent. They lose nothing by being real villains and they gain quite a bit. Slow and murky and alien.
Eyes are, if not the window to the soul, then at least supposed to tell you quite a bit about the soul, and an animal without eyes can't help but seem sinister. The floating brain in a jar is never a good guy. The jellyfish monster is like the floating brain in a jar adapted for life out in the world--sleek and malleable and with its translucent head full on invisible thoughts.
I'm glad that the worm is purple.
Purple is regal (because it is rare), purple is weird (because it is unnatural in animals), and purple is pulpy (because pre-twentieth century imagination rarely dreamed of purple animals). If it were just a giant worm it would just be another gross thing only big. The purple worm has a dignity granted by it's exoticism. In the original illustration it's black (one of the two available colors) which suggests it's the color of grape soda--black for the most part, but a rich violet in the highlights.
Someone will no doubt point out in the comments that it was originally unillustrated and spelled purple wyrm with a "y"and so maybe was some kind of dragon. I imagine that beast as being kind of perfect in its unimaginableness. I'm instead thinking that the Purple Wyrm should never be imagined, visualized, or illustrated, not as a cartoon purple dragon and not as one of TSR or WotC's athletic uber-lizards with a different palette but instead as some entirely literary cousin of a dragon. Like the questing beast or the bandersnatch or the boogeyman, the purple wyrm should never have a miniurature and should be spoken of only in reverent and hushed tones.
Ice, smoke, magma, and ooze. I've already complained about how boring ordinary elementals are, why not have all of these guys on the chart too--or instead? Magma is good--probably best represented by those big red guys who fought Crystar the crystal warrior and the lava children.
Smoke, ooze and ice, unlike air and water, actually have an emotional meaning.
It it strange that the phoenix didn't show up until the Monster Manual 2. I like it understated--a small beautiful red bird that just happens to live in fire and is also unimaginably important and magical.