Help me populate a dungeon crawl?

[Grod_The_Giant]

In the upcoming few weeks, my players are going to be working their way through what I've been advertising as a more old-school style dungeon crawl. They've come to the wreck of an frost giant Ice Breaker, a sort of fast-moving glacier castle-ship thing, looking for some clues as to how the villain got a spellbook from it, and what else he might have taken. Problem is, I'm not sure what to include. The party is a mix of level 3s and 4s-- a fighter, paladin, rogue, sorcerer, and I think a monk and ranger will be joining. I'm looking for ideas for both encounters and for generally interesting rooms to populate the ship with. Ideas so far include:

A wrecked "engine room" currently shrouded in subzero temperatures, with one last ice elemental running loose-- out of its hamster wheel, but unable to fully escape the ship
Slave pens full of frozen corpses, with an angry ghost animating them to strike back at the "captors" who've clearly come into the room to drag more slaves away.
Angry undead in the officers' quarters, forever acting out the ship's last moments and reacting violently to disturbances
Another opposed adventuring party
Gun decks full of broken catapults and low-level constructs (refluffed blights?) who once tended them.
The ol' "roof full of razor-sharp icicles, ready to come crashing down at the slightest noise." Big dumb brute to come crashing in after them optional.


Can anyone help?

[lunaticfringe]

Remorhazes

Either a Young Remorhaze as Boss Fight or a Remorhaze a Chaser. A big scary thing that chases the PCs around the Glacier sized ship or Railroads them into sections of the ship you want them to explore.

Manly Viking Looters/Murder Hobos who are just having a good time and are willing to sell/trade stuff with the PCs (for resupply purposes/downtime interludes/advice on what's ahead).

Coocookachu an awakened walrus Wizard King of Walruses(or something), BECAUSE!

[MasterMercury]

Just look in the back of the DMG if you have it. Monsters by environment: arctic. Tons of ideas there.

[HammeredWharf]

If it's a ship, it could have a cargo room. A cargo room could have some old merchandise in it, such as crazed old golems, explosives, barrels of acid, poisonous plants and other fun things one would sell in a D&D marketplace. Other than that, it's a wreck, so something sunk it and I assume you know what that something was. It could still be stuck in the ship, or it could've turned the ship into its nest, or it could've left some (dangerous, of course) traces of its visit. It could be a good boss encounter, if you fill the dungeon with clues about what happened and maybe some hints at the creature's weakness.

[SillyPopeNachos]

How about a Yeti or two?

[Grod_The_Giant]

If it's a ship, it could have a cargo room. A cargo room could have some old merchandise in it, such as crazed old golems, explosives, barrels of acid, poisonous plants and other fun things one would sell in a D&D marketplace. Other than that, it's a wreck, so something sunk it and I assume you know what that something was. It could still be stuck in the ship, or it could've turned the ship into its nest, or it could've left some (dangerous, of course) traces of its visit. It could be a good boss encounter, if you fill the dungeon with clues about what happened and maybe some hints at the creature's weakness.
Unfortunately that's not a mystery; the party knows that it was wrecked by war mages during an attack on human colonies.

[Shining Wrath]

Sounds like a lovely place for a Frostwind Virago. Too powerful for this party, of course, but as a I-will-let-you-live-if ... encounter it might work.
You can do the classic "room fills with water" trap - party moves some big thing so they can get at that interesting looking chest behind it, and it turns out the big thing was all that kept a board from popping loose and letting the frigid waters into this room. Will the cold damage get them before they drown? Will they think to push the heavy thing back into place and thereby slow the flow? And what, exactly, is in the chest?
Not-zombies. A variant on mammalian diving reflex caused some of the crew to go into a stasis, with a metabolism slowed to 1 heartbeat per day. If the party lights a fire or otherwise makes the "corpse" warm, a reawakening occurs and the creature returns to activity. It may or may not be grateful. The party may or may not realize that they are dealing with a living creature, not a zombie.
A polar bear smelled the corpses one not-as-cold summer day but couldn't work out how to get at them. Since then, though, the bear has viewed this ship as a potential larder and driven away intruders. If the party opens the path to the corpses the bear will become frantic. I leave what "frantic" means, mechanically, in your capable hands. I imagine, though, that the party will be exploring a room full of corpses cautiously, watching for undead / traps / treasures, and suddenly a bear comes through the door at full speed - and of course a polar bear has traction on ice, and the party may not.

[Temperjoke]

How old is the wreck? Maybe the giants had a captive pet white dragon that's survived somehow and made the wreck into a lair? Frost giants also keep trophies from enemies they conquer, so there could be an assortment of weapons and armor in various conditions and quality, valuable items like ivory tusks, maps and charts that might have old information labeled that has been lost to modern scholars, etc.

[Joe the Rat]

How long wrecked is it?

- Having some livestock get loose from the larder could make a merry chase. Boars are tasty AND dangerous

- Winter wolves. They've moved in to use the hulk as a den.

- Frost ooze. Looks like an ice slick, stats like a grey ooze or ochre jelly.

[Grod_The_Giant]

It's been wrecked for a few years.

[Fable Wright]

There's a white dragon corpse in the hold.

Mostly decomposed, riddled with PC-attacking parasites, and its death-curse and lifeblood have mingled in the room, causing a combat-warping effect. (No healing, or wounds freeze causing additional cold damage while increasing armor class, or wild magic, or...)

Much of the body has been eaten, but a few parts have been surgically removed. Recently, in fact. If the PCs make a knowledge check or consult a sage, they can recognize what the liver, thyroid, and floating rib of a dragon are used to craft, giving them a clue towards the purpose of the mage they're hunting.

Potentially, you could also have the vault where the spellbook was stored. It used to be a prismatic wall, captured in eternal ice, invulnerable to virtually all forms of attack. And yet, the ice is somehow broken, with varying colors stored in the different pieces. It's a strange and fairly distinctive form of magic that can do this, which acts as a clue, and the room doubles as a challenge/loot: The shards fill the area and function similarly to caltrops, but with a catch: If you get cut by the a shard, its effects take place on you. If you break the shard, the magic flings out in a random direction.

If the players can somehow fashion these unmelting ice shards into shivs, they gain useful and interesting oneshot weapons... but they're trying to avoid getting cut in a field of knives that have melted and refroze into the floor.

[Zippdementia]

Just a note: if you truly have six characters playing, you may very well need to up the challenge from what you would normally throw at a party of this level. The action economy is FAR in favor of the players, if they have six players.

Aside from that, consider having the ship itself be possessed, or otherwise "alive." Think doors slamming shut, trapping them in with monsters—or opening to allow freezing water in. Railings coming to life like tentacles, trying to throw players off the ship or suffocate them. Floors giving way, dropping players into the dark bowels of the ship, where awaits greater terrors...