Today's monster is a bit of a challenge. I want a tough creature that's size "tiny."
Most tiny creatures in D&D 5E feature very low Challenge Ratings (0 to 1). If we look at the more powerful ones, like older Faerie Dragons, Flameskulls, Demiliches, Imps, and Will-o'-Wisps, we see one prevailing trend: flight. Makes sense; it's hard to envision a dangerous, tiny creature that can only bite your feet.
Let's go nice and fantastical and create a crystalline creature. Imagine a precious gem mine that also sits on a ley line, which sometimes breathes life into the gems, turning them into insect-like creatures that flitter about the caves. Not only does that feel magical, we can easily expand that into larger or smaller creatures.
Let's start by comparing basic stats for two other flying CR 2 tiny creatures: The Will-o'-Wisp and the Faerie Dragon.
|Fly speed||60 feet||50 feet|
|Melee attack||+7, 1 damage||+4, 9 damage|
|Ranged attack||DC 11 Wis save or confusion||none|
This isn't a complete picture of either monster, but we can see from the wide range of stats that we have plenty of room to design.
I imagine a crystal creature being relatively easy to hit but hard to break, and resistant to many kinds of damage (acid, cold, fire).
But that's not enough to create a truly memorable creature. Given that these creatures magically manifest in mines, what if we think of them as colonies? And what if their attacks deal more damage if several of them are nearby? This would push PCs to change up their tactics, possibly grabbing enemies to keep them separated.
Let's increase the weirdness by eschewing the boring old bite and bash attacks. How about a short range electrical attack? That would explain the increased damage; each creature amplifies a nearby creature's electric charge.
We'll polish it off with an ability that makes it indistinguishable from a normal pile of gems if it sits motionless in a crystalline environment. That's more flavor than anything.
OK, I think we have a crystal wasp!
Homebrewery stat block:
tiny elemental, neutral
- Armor Class 15
- Hit Points 20 (8d4)
- Speed 0 ft., fly 40 ft.
- Damage Vulnerabilities thunder
- Damage Immunities lightning, poison
- Damage Resistances acid, cold, fire, necrotic; bludgeoning, piercing, and slashing from nonmagical weapons
- Condition Immunities poisoned, prone
Gemstone Camouflage While in a gemstone cavern, a crystal wasp motionless on a wall is indistinguishable from a normal gem formation.
Lightning Arc. +5 to hit, reach 10 ft., one target. Hit: 3 (1d6) lightning damage, plus 3 (1d6) for each crystal wasp within 15 feet (maximum 9 (3d6)).
I'll make some variations on this in the future. Imagine a mine full of crystalline creatures, relentlessly and sleeplessly stalking the unsuspecting adventurers....