D&D 5E Weird and terrible things to go into a collection

[TheSword]

So I want to have a Mind Flayer agent and intermediary who is quite rich and successful. He has collected all manner of ancient and wicked objects, some magic, some just unique. If anyone has read the Ravenor books then Orfeo Culzean is an inspiration for him.

I want the final boss fight to take place amongst his collection. With it containing weapons, constructs and strange creatures either in cages or glass cabinets etc that the mindflayer can release or activate during the fight.

The important thing is that anything in the collection could possibly be obtained by the PCs so from a power point of view I want things to stay reasonably balanced. Party has a wizard, a rogue, a Paladin and a cleric. They are all level 8. It’s Forgotten Realms setting.

What kinda of things would be cool in the collection?

 

[BookTenTiger]

A collection of tortured dreams! Crystal orbs in which the mind flayer has syphoned the dreams and desires of his victims. But the dreams are twisted so that the piece of their mind trapped in the orb is forever tortured.

If an orb breaks, it releases powerful, chaotic psychic energy that can either inspire someone with a dream or torture them with a nightmare.

 

[Stormonu]

A brain in a jar (whose attached eyes watch the fight closely); if the PCs break the lead-lined glass jar that block its psychic abilities, it can get off a few psychic blasts at the mind flayer before expiring, or the mind flayer could attempt to eat it to regain health or uses of its abilities.

 

[Umbran]

What kinda of things would be cool in the collection?

I might suggest perusing the pages of the Mütter Museum for inspiration.

 

[CreamCloud0]

Various rare books,
a set of high quality tools,
fine clothes,
bits of weird creatures(scales of a leviathan, the horns of a dragon, the feathers of a pheonix),
an imp or suchlike that bonds to whoever frees it as a familiar,
potions or scrolls for the flayer to potentially use in the fight,
pieces of treasure that have more cultural value than monetary,
various ‘X in a bottle’s(a storm that pours rain covering the floor and the occasional lightning bolt, vines that cover a radius with difficult terrain, a tornado that pushes everyone 10ft in your chosen direction once a round),
I don’t know if you want to put in some low level magic gear for the purpose of intentionally having it looted but having the flayer use them against the players in the fight beforehand leaves an impression,
magic items that are more curios than practical(a harp that plays music by itself, a potted plant that grows flowers of ice, an artificial bird that flies around the room, a lantern that produces light of any colour)

 

[BookTenTiger]

A collection of screaming skulls!

These are skulls collected from the bodies of tortured victims. They still possess a fragment of the pain and suffering inflicted on the body that possessed it. When disturbed, the skull emits a piercing, terrible scream, disrupting Concentration and making communication difficult.

 

[steeldragons]

Not to get bogged down here...I have to get moving...but a few things that just jumped to the top of my head... it's a Mind Flayer big bad...so presumably its collection is going to be an assemblage of acquired rarities of evil and wickedness that few others would know of or could even begin to try to find and artifacts/souvenirs of conquered foes/victims...presumably the bulk of which are going to slide toward to "good" and/or "lawful" side of the scales...So,...

• The horn (possibly stored in a jar along with a half eaten brain) of a Kirin.
• A mid-sized apothecary jar containing an apparent tiny storm cloud. Occasional streaks of lightning illuminate dark grey thunderheads give way to muted cracks and rumbling of thunder. Occasionally, the clouds swirl into a whirlwind that twists about within the jar for a time before forming back into billowing clouds. Opening the jar (perhaps during the fight) will release the Djinn trapped within. He will be all too happy to engage/destroy his captor.
• A scroll of pure silver (that rolls and unrolls as easily as paper) that holds a map to the <lost/forgotten/thought destroyed> <city/nation/realm> of <lost/forgotten/untold> magic and riches.
• The pitchfork of a malebranche/horned devil.
• Three small pieces of amber. Close inspection reveals within each is contained a miniaturized deva, weapons brandished, wings spread apparently in flight, dramatic poses. They were, in fact, real devas but are fully/truly deceased, frozen in the amber.
• The mummified head of a shedu (or sphynx?). If activated/animated somehow (DM can chose how), it will answer any three questions truthfully... Or, maybe, instead, utters some kind of prophecy (presumably warn of some evil or something to further the cause of Good)... that's all the shedu's soul/spirit was able to leave imparted on its mind. It can/will repeat the prophecy/verse as requested.
• Several jars containing the heads of various sapient species: various kinds/colors of human, a couple of elves, a dwarf, maybe a tiefling or something more exotic. Some have hats or head covering or jewelry (earrings, headbands, etc...) still intact, some may be of cultures the PCs do not know/recognize. All have eyes wide and mouths agape in twisted horror. All have the rear of their skulls broken open/holes bored into them. All of the brains are gone, of course.
• A jar with a very bored, but very much alive, homunculous of some long dead alchemist from a previous age. Generally disagreeable and gruff, but has a great deal of [accurate] alchemical knowledge that it will grudgingly share if you can win its trust... and in exchange of crackers or (preferably) cookies. Gods help you if you try to give it a vegetable!
• A rather large jar containing, a preserved-in-some-liquid, fair-sized tentacle (a section of an aboleth tentacle)
• A massive (two handed for PCs, for sure) silvery lightning bolt-shaped sword. A balor/type VI demon's sword - who may or may not (DM's choice) still be alive/exist and may or may not (DM's choice) be interested in getting it back.
• The highly magical shield of <setting mythic hero/champion of good>, perhaps not even thought to be a historical/"real" person to the PCs.
• A golden disc, about 10"-12" plate or platter, etched around the edges with multiple circles and mystic characters. Cursory arcane investigation/detect magic/arcana checks immediately note them to be "very advanced" sigils, Abujration in nature. Within the gylphed circles of the plate sits a human-looking skull with gemstones in the eye sockets and several square-cut gems as "teeth." Yes, it's an actual demi-lich. The demi-lich's spirit is far afield, pursuing arcane power across the existential planes. It's skull has been placed -perhaps by the mindflayer, perhaps someone else- in a magical "statis" to prevent the demi-lich's unexpected return. Any disturbance of the symbols, however, or removing the skull from the plate (it can, afterall, just be picked up) and things could get...very bad, very quickly.

Right. On with it. Good luck. Enjoy.

 

[Scars Unseen]

• A pair of trousers with pockets dimensions
• A treant seed
• A broken clock that will accurately answer a single question about the indoor room it sits in twice daily
• A small sack of gold coins that can be used to track any coin removed from it. Each coin can only be used once before losing its magic.
• A key that will unlock any door. After an unknown number of uses, it instead opens a door into the parlor of the devil who crafted it.
• A small silver mirror with a bit of verse inscribed around the border. When first gazed upon, the mirror briefly reflects the face of the previous owner before showing the user's own reflection. If the user speaks the verse while looking directly into the mirror, they lose one ability score point (randomly chosen) and grow a number of years younger equal to 1/10 of their maximum lifespan. Alternatively, if they speak the verse while smearing the blood of someone killed for the express purpose of invoking the mirror's magic, they gain the same number of years at no personal cost. Even without invoking its magic directly, the user must hold the mirror and speak the verse (with or without looking into it) in order to confirm ownership. Failing to do so results in the mirror vanishing and coming into the possession of someone who has seen the user's face in the last year.

 

[GuyBoy]

A collection of screaming skulls!

These are skulls collected from the bodies of tortured victims. They still possess a fragment of the pain and suffering inflicted on the body that possessed it. When disturbed, the skull emits a piercing, terrible scream, disrupting Concentration and making communication difficult.

And if you wanted to be truly awful, have one of these skulls (a more recent one) be somebody linked positively with one or more of the players.

 

[Quickleaf]

A trembling nothic that is bound and facing a mirror, its single eye pinned open, so that it is forced to gaze into its own dark secrets.