Exploring With Spells in the Megadungeon

Found at Angry Golem Games

Continuing the thoughts from last week, I thought I would discuss some of the more versatile spells in a megadungeon environment. With literally thousands of spells designed for D&D and its relatives, some are obviously going to be more suited to dungeon environs than others. 

I am using the Labyrinth Lord spell list primarily today. I am not looking at combat (or role playing) applications for the spells, instead, they must be useful within the exploration phase of the game. 

Most "exploration" spells fall into a few broad categories: Blocking, information, movement and resources.

• Blocking spells protect your flanks (like Arcane Lock)  
• Information spells give you the ability to make smarter choices (like Light, Commune and Clairvoyance).
• Movement spells allow access to areas that would be difficult or impossible to reach without them (Fly, Invisibility, Lower Water, and others)
  
• Resource spells protect or gather more resources to more efficiently explore the dungeon (Purify Food and Drink, Dispel Magic, Floating Disk).
  

Clerical Spells
Commune: Any spell that gives you information is useful in a megadungeon. 
Continual Light: Light is possibly the most precious resource in the dungeons. This spell is possibly the best spell that a group can have access to. It is most useful when cast on several object (that can be easily concealed) before entering the dungeon. Even if everyone in the group has darkvision, Continual Light allows for reading script, discerning colors (possibly solving a puzzle or trap)and seeing discoloration (like where a secret door may open). Light  is useful in the same way, but not permanent.
Detect Spells (Evil, Lie, Magic): Information is always useful. When interrogating a prisoner, know if they lie. Detecting evil behind a door may just save a life. And knowing what is magical garners too many benefits to list here. 
Dispel Magic: Too useful in all aspects to ignore. Remove illusions, Arcane Locks, and other hazards with relative ease. 
Find the Path: Know how to get out. Guaranteed.
Find Traps: This name speaks for itself. Don't fall prey to the insidious traps that kill so many adventurers. 
Locate Object: Unless you are close to the exact object you seek, and you have seen it before this spell is less useful than it seems. It is best used to find things like water, food or ways to bypass obstacles (like a lever to raise the portcullis).
Lower Water: With some research and fore-knowledge this spell can grant access to hidden parts of the dungeon. Just do your research before memorizing this one.
Purify Food and Drink: A low level party often has low level resources. This spell stretches those resources, and can often be useful in tempting situations (like walking into a fest-hall with a fully furnished table).
Resist Cold/Fire: These spells allow access to dungeon areas that are difficult to reach without them.
Silence 15' Radius: Most people try to silence spellcasters with this one. Instead, try sneaking past the orc barricades, or that room that drops boulders on your head when any noise is generated. 
Stone Tell: Anything the local stone has seen, it can tell you about? In the right place, this spell can gather more information than any other.
True Seeing: A true get-out-of-jail-free card. Know what is what around the character. Illusions? Pshaw! Secret Doors? Nope. Invisibility? More like no-ability. Once access is gained to this spell, it should always be memorized in a dungeon environment. It has uses in all three pillars of the game (exploration, combat, and role-playing).
Wind Walk: Another spell that allows access to places that were beyond reach. 
Word of Recall: Get-out-of-the-dungeon-free. Sure, your friends probably aren't coming with you, but that's why the Magic-User memorized teleport, right?

As a 1st level cleric, I would enter most megadungeons with Light memorized, with Detect Evil, and Cure Light Wounds as solid options as well. (If I am playing a character with darkvision, that switches to Detect Evil).

As a 5th level cleric, my spell list would be: Detect Evil, CLW, Protection From Evil, Find Traps, Silence 15' radius, and Dispel Magic.

Arcane Spells
Arcane Eye: An information gathering spell that keeps the group (relatively) safe.
Arcane Lock: Make sure nothing is sneaking up on you. Or have a safe resting place. Either way, it is a bargain for a 2nd level spell.
Clairvoyance: Like Arcane Eye a spell that gathers a lot of information at little risk.
Contact Other Plane: Akin to Commune, only take this if the cleric didn't take the other.
Continual Light and Light: See clerical descriptions.
Detect Spells (Evil, Invisible, Magic): Same as the clerical spells. Detect Invisible is less useful in the exploration phase than in combat, but can still see some play (for example a key may be invisible that allows access to a treasure hoard.)
Dispel Magic: covered in the clerical list
Fly: There are often huge drops in caverns and crevasses. Fly makes it easier to navigate.
Hold Portal: Keep the door shut for a couple of hours. Long enough to get away.
Infravision: As has been discussed ad nauseum sight is a primary resource. Infravision may allow for seeing heat radiating from behind a wall or within a chest. Any unexpected heat source should be investigated.
Invisibility, Invisibility 10' Radius: These spells allow bypassing of a potentially dangerous encounter, similar to Silence. Just make sure that you have a plan to get back out.
Levitate: Vertical movement is often the most difficult. Levitate makes those high and low areas more accessible. It may be negated with a rope and grappling hook, though, depending on circumstances.
Limited Wish  and Wish: No brainers. Spells that give you a wish-come-true are useful no matter where you are or what phase of the game you are in.
Locate Object: See clerical version
Lower Water: See clerical version
Magic Jar: This spell can allow unfettered access to areas that are controlled by creatures hostile to the caster. Use it to map out and explore these areas before the assault. Just make sure that your fellows protect you while you are away.
Passwall: Shortcut through the dungeon. It only stays open for 30 minutes, so be quick. But, it can bypass traps, groups of enemies, puzzles, and other hazards.
Phase Door: Similar too Passwall, this spell has the added advantage of being difficult to detect. It has the drawback of being very limited (6-10 uses in total). 
Read Languages, Read Magic: Often while exploring, the party will come across strange glyphs that have information, if they can be deciphered. Having these spells available has the potential to gather a lot of information at little risk.
Telekinesis: Think something is trapped? Use this to manipulate it. Can't get across the portcullis to pull the lever to raise them? TK is your answer. Any time something needs to be manipulated, this spell is potentially useful.
Transmute Rock to Mud: Another shortcut spell. 
Water Breathing: Water features often hide great treasure. Be the one with the ability to recover it.

When entering the megadungeon as a 1st level magic-user, I would prepare Read Languages. First delves almost always come across some writing that will be useful to the group. 

As a 5th level magic-user, my spell list is: Detect Magic, Magic Missile, Arcane Lock, Web, Dispel Magic (unless the cleric has it) or Clairvoyance.

Having the correct spells available for exploring the megadungeon can be the difference between life and death. At the least, using exploration spells allows you to make informed decisions on where, when and how to fight.