Apprentice's Spellbook
Who's That Monster?
RAW
Cave of Wonders
The Letter A
100
This is the distance of bright light that the Light cantrip creates.
What is a 20-foot radius?
100
This creature tends, feeds, and watches over spiders the way a shepherd oversees a flock of sheep. They lair deep in remote forests. 
What is an Ettercap?
100
This is the base swimming speed of the Triton player race.
What is 30 feet?
100
This is the item that can produce 2 gallons of mayonnaise per day, amongst other things.
What is the Alchemy Jug?
100
The first entry of the Monster Manual.
What is an Aarakocra?
200
The maximum length that the Wall of Fire spell can reach.
What is 60 feet?
200
Tharizdun, the Chained God, created these creatures to devour planar travelers who were seeking portals that lead from the Astral Plane to the Outer Planes — it also contains within it a pocket Demiplanar Donjon.
What is an Astral Dreadnaught?
200
The amount of extra hitpoints a level six bard restores to their allies when playing their Song of Rest.
What is 1d6?
200
While worn, this item projects an illusion that makes you appear to be standing in a place near your actual location, causing any creature to have disadvantage on attack rolls against you.
What is the Cloak of Displacement?
200
This item sets your constitution to 19, though it has no effect if your constitution is 19 or higher without it.
What is the Amulet of Health?
300
This concentration spell provokes intense paranoia - Whenever the affected creature chooses another creature as a target, it must choose the target at random from among the creatures it can see within range of the attack, spell, or other ability it’s using.
What is Enemies Abound?
300
This creature reproduces by forming nodules on their bodies that, upon reaching maturity, break off to begin life as their young. It has an overpowering need to bond with an intelligent creature.
What is a Gray Render?
300
When using Teleportation Circle as this subclass, you open a portal to the last location where you finished a long rest on your current plane of existence.
What is the Circle of Dreams?
300
This rare item allows you ignore difficult terrain, and magic can no longer reduce your speed nor cause you to be paralyzed or restrained.
What is the Ring of Free Action?
300
A new playable small race in the Travelers of the Multiverse Unearthed Arcana that is a construct.
What is the Autognome?
400
This spell creates an aura that grants nonhostile creatures an extra 1d4 radiant damage when it hits with a weapon attack.
What is Crusader's Mantle?
400
This creature is a potent, spider-like construct conceived and built by the drow for one original purpose — to prowl the Abyss and capture demons for the drow to enslave or use in their rituals.
What is a Retriever?
400
This is the spell that the Echo of Dragonsight allows you to cast as a ritual.
What is Contact Other Plane?
400
Daily Double!
While holding this item, you can use an action to expend 1 charge and cause a flower to sprout from a patch of earth or soil within 5 feet of you, or from the item itself. Unless you choose a specific kind of flower, a mild-scented daisy is created.
400
While affected by this spell, the object is more difficult to break or force open; the DC to break it or pick any locks on it increases by 10.
What is Arcane Lock?
500
This spell duration lasts 10 days and requires either a lump of alum soaked in vinegar or a drop of honey, depending on its intended effect.
What is Antipathy/Sympathy?
500
Daily Double!
These creatures are all that remain of people who fled into the Shadowfell to escape their mortal existence. There the darkness transformed them, and their bitterness made them twisted and cruel.
500
This is the construction time listed for a Temple in the Dungeon Master's Guide.
What is 400 days?
500
This legendary item grants you a +3 bonus to armor class, renders you immune to fire damage, allows you to speak Primordial and allows you to walk across molten rock as if it were solid ground.
What is the Efreeti Chain?
500
This is the country ruled by Queen Aurala ir'Wynarn in Khorvaire, and its capital is Fairhaven.
What is Aundair?