Monsters of the Mythic Underworld

These monsters are natives of the Mythic Underworld.  The Dungeon beneath all dungeons.  The darkened halls that we all visit in our earliest nightmares.  The liminal ur-space that borders Hell as well as your grandmother's cellar.

These monsters don't necessarily have a full history, biology, or psychology.  (This is probably because I couldn't come up with anything good.)
That's okay.  They're still good monsters.

I've mostly not bothered with full stats.  Assume AC as chain, improvise the rest.  You'll be fine.

a False Hydra by NisseLindblomArt

Buggy Birds

Level 1

Actually an insect, a buggy bird is about the same size and shape as a heron.  They look majestic in profile, but a bit ridiculous the rest of the time.

Pedants will point out that, actually, they should be more accurately called "birdy bugs".  This is why the traditional punishment for pedantry is Impalement by Buggy Bird.

Spend one round retracting their head, inflating their chest, and cooing.  On the next round, they attack for 3d6 damage and make a horrible BWEAGH noise.

Attercop

Level 2  Dagger 1d6

About the size of the smallest guy in your high school class.  Tusks like a boar.  Nose like a skull.  Each eye is a gem worth 10s.

Can shoot webs from their hands and swing from them.  Can shoot webs onto foes, entangling them.  Can create bungees and slingshots.  Can spend two rounds shooting a web to two points, and then create a line between them.  Can create inelastic webs if needed.  Capable of huge leaps.  Can climb up sheer walls.

Can the DM think of a new way to use this ability every turn?  The DM can, because the DM can google spiderman as well as anyone else.

Attercops hate spiders.  They hate being compared to spiders.  They hate anything spidery.

Attercops don't lay eggs or weave webs.  (Although they do weave tripwires, alert wires, ropes, and nets.)

Attercop is a last name.  They are an example of what happens when a cult successfully completes their master plan.  They are irredeemably evil, and believe that everyone else is prey.  But they are a family in the Legal* sense.  If you marry into the family, you will gain their mutation and skewed perspective.  If one of their sons disowns them and everything they stand for, you will lose it.

*I mean legal in the sense that the Authority recognizes your marriage, and therefor the universe does as well.

Demonoid

Level 3  Weapon 1d8

Rapacious -- The demonoid makes two melee attacks against its target.  The target makes one melee attack against the demonoid.  All three of these attacks happen simultaneously.

A demonoid is what happens when a demonic possession is never cured.

This is not to say that the demon that is possessing this poor man is the same demon that originally possessed them.  It is far more likely that the original demon sold the body after they tired with it, and so on and so on, over the long years, until the body ends up in the possession of some idiot.

'Orrible Gregory

Level 4  Claws 1d8/1d8  Climb

They look like bipedal crabs with the heads of fat-necked vultures.  They are famously ugly, but adore cute things.  (Their babies are famously cute.)

Can replace one of their claw attacks with a hook pull, which pulls the target creature adjacent.  Str/Dex negates.  30' range.

Their tendons can be harvested for use as ropes.  They take up 1 slot, but are twice as long (100').  They will rot in 3 days unless preserved.  They hang out near ledges, bridges, and dark cave entrances.

Replaces hook horrors, which are kind of lame.

Zephrus

Level 5  Grab  Fly 10

The most well known of the wind golems.  It looks a bit like a complicated octopus made from ropes, prayer ribbons, and metal coins.  At the center, something like a dream-catcher woven around a brass ring.  

Once it grabs someone, it starts casting scatter to the winds.  Everyone has one turn to react, but if the target is still in the zephrus' grasp at the end of that time, they are teleported to a random room.

A zephrus "in the wild" will teleport you to a random room on the same floor.  A zephrus that is created for a particular purpose will probably teleport you to a furnace, a cage, or a pit next to a wyrm's nest.

There is at least one story that tells of a thief who painted himself gold, held very still, and tricked a zephrus into teleporting him into the vault.

If killed, the brass ring of the zephrus can be used to cast scatter to the winds simply by passing an object through it.  (Object size must be between a chest and a large human.)

Ancient Eldrox

Level 6  Grab/Grab/Grab
Fly slowly
Casts as a level 4 transmutation wizard.  You can cut off tentacles fairly easily, but it takes no damage until you crack its obelisk by dealing at least 6 points of bludgeoning damage it.  If they grab you,

Basically just a flying obelisk with a bunch of tentacles coming out the bottom.  Smart people avoid reading anything on it.

At the start of its turn, all held creatures take 1d12 damage from biting and/or neck-wringing.

They're very evil, but their machinations are directed elsewhere.  Humans have little ability to help or harm their plans.  Because of this, they're also kind of friendly. 

They usually start off by essentially asking you a trivia question.  If you get it wrong, they decide that you are useless and will be hostile.  If you get it right, they will decide that you are useful.  They will give you a small reward (fancy boot, bottle of pear cordial, a kitten) and ask if you want to be friends.  This is a pact of mutual non-aggression and nothing else--they will still be suspicious and weird.  If you give them a gift, they will give you a slightly better gift from their stash.  They will not be out-socialized by a mere human.

"YOU MUST ACCEPT THIS GIFT!  FAILURE IS AN INSULT!  I WILL NOT BE INSULTED!"

They may offer to rent you by implanting an embryo inside you.  (It will puppet your body for 1d3 sessions in a distant location, during which you'll have to play an alternate character.)  Afterwards, the embryo will remain with you, visible inside your abdomen (because it can make your skin translucent), where it will let you cast a random spell per day. and happily dispense Forbidden Knowledge.  If anything weird happens while you're sleeping, it can kick your kidneys to wake you up.

The unborn eldrox will be sad because you are not smart enough, nor big enough, to carry it to maturation.  Although it could attempt to grow to maturity inside you, it knows that such an attempt would probably result in the death of you both.  If only you could somehow get much bigger and smarter, we might be able to make a deal. . .

Panoptigore

Level 7  Def plate  Sword 1d12
Can cast ganonball and fear.  2 MD.

An floating, armored giant with a single eye and no legs.  Magnificent cape.

Gaze Attack -- If you meet the gaze of the Panoptigore, you instantly create a side combat.  The side combat lasts 1 round and takes place inside the Panoptigore's eye, a spherical space 50' in diameter.  All of these sub-combats occur instantly, and are always 1-on-1 fights.

If six people lock eyes with the Panoptigore, then six separate 1-on-1 fights occur instantly.

New Spell: Ganonball
A ranged attack roll that does 2*[sum] damage.  Opponent can reflect the ganonball at a new target by beating your attack roll with an attack roll of their own.  (If it can make an attack roll, it can reflect a ganonball.)  Ganonballs can be hit back and forth as long as people keep rolling higher than the previous roll.  All this back and forth is resolved instantaneously.