Here is my contribution to the d-Infinity Live! Fine Art Challenge. The challenge prompt was to create some sort of setting and three elements of game content based on the works of a named artist. I chose to draw inspiration from the work of Surrealist Rene Magritte. Below is a brief description of a one-shot adventure suitable for any number of fantasy or sci-fi settings. The "monsters" are statted for 5th Edition Dungeons and Dragons. 
 

Cure at the Castle of the Pyrenees

An adventure inspired by the works of Rene Magritte

The setup for this adventure is that one of your party has fallen ill with a mysterious ailment: their skin appears to slowly be turning into wood. No divine or arcane magic has been able to cure them, no potion (however expensive) has reversed the effects of their strange affliction. Druids scratch their heads, not recognizing the variety of timber that is replacing your friend's flesh. It's getting harder for the afflicted to move around and function, and the party fears that soon they will be rendered completely immobile. As they desperately search for answers they catch wind of a rumor: broken accounts of a faraway place where an enigmatic figure resides: The Healer.

The adventurers set out toward the Forest of Light – an unsettling place where it is always as dark as night among the trees even when the sunlit sky can be seen overhead. The party may be confused and disturbed by the strange way the spaces between the trees can seem to block or cut up objects that should be plainly visible, or the way the sun and moon seem to hang just a few feet away in the darkness, but no harm comes to them there. After a day's journey they reach the other side. There is a long, rocky beach leading down to a rough patch of ocean. Just a quarter mile out, hanging in the air above the water is a giant levitating boulder with a stone keep perched on top of it. They have reached the Castle of the Pyrenees.

After the party makes a few attempts at reaching the floating island and scaling the formidable rock face, a stranger appears on a ledge near them. The figure is most likely human, clothed in only a light robe, and has a blank expression on its androgynous face. It introduces itself as The Guide. With a wave of its hand a staircase appears in midair, allowing everyone to safely walk up to the keep. The party is led into the Castle, which is full of clean and sparse halls and rooms. The few objects that can be found are strange and off-putting: candles that trail and wrap around furniture like snakes, stone fruit and empty glass chalices in little shrines, a pair of boots that are fashioned to look like human feet, marble busts with strange splashes of blood red paint on them, and other curiosities.

Eventually the party is led to an open balcony overlooking the ocean. Seated close to the stone ledge is a very strange sight: it appears to be a birdcage containing two white doves, half covered by a heavy red cloth. However a pair each of clothed arms and legs protrude from the drape and a small straw hat is perched on top of the cage. One hand holds a cane as if this creature were resting on it, and the other tightly grips the top of a dark leather sack that is set on the floor. The Guide introduces this bizarre being as The Healer.

The Healer doesn't speak, but gestures to the suffering adventurer with it's cane to come closer. The Guide explains that one must cover with the drape, open the cage, and receive the doves' song to be healed. Once the adventurer complies they find that indeed – their horrible affliction is gone. The party rejoices! But, The Guide interrupts, now it is time to pay the price.

The Guide tells them that in payment for the service of curing their party-member they must give up something valuable: their very face. The Healer shakes it's leather sack expectantly. When the party reacts in horror The Guide assures them that the adventurer can select any number of fine replacements from around the Castle. Fruit or flowers are always a favorite. If the party tries to flee, The Guide pursues them and will try to take the indebted adventurer by force. The Guide is a respectable opponent in a fight, but once the party causes enough damage, its face falls off – revealing an interior made of wooden contraptions, including many strangely seamed spheres that don't appear to have any real purpose.

Having defeated The Guide, the party will flee the haunting halls of the Castle of the Pyrenees, (a task made more difficult by the fact that the staircase they used to reach the top of the island has disappeared) but they are not free from danger yet. After reaching shore by whatever means, they head back to the woods. As they cross a small open field between the beach and the treeline another bizarre apparition suddenly appears. A set of three giant metallic spheres hang in the air before the party. They have the same seamed appearance as the small wooden spheres from inside The Guide and they give off a threatening aura. Any adventurers of a race with especially good hearing immediately begin to feel unwell and suffer a terrible headache. If they party tries to escape these foreboding bodies they feel an uncanny resistance and their life starts to be stripped away bit by bit. Only by fighting and destroying the spheres can the party escape and live to fight another day.

The Healer:

Appears to be a birdcage containing two doves, covered on all but one side with a red cloth, with humanoid arms and legs. Carries a cane and a leather sack full of magically preserved faces.

Hit Dice: 2

Alignment: Neutral

AC: 10

Size: Medium

Number of Attacks: N/A

Damage/Attack: N/A

Special Attacks: The Healer won't attack characters or even defend itself if attacked.

Special Abilities: Once per day The Healer can cure a magical ailment on another character by wrapping it in its cloth and having the doves in its cage sing. After curing a magical ailment The Healer can then wrap that same character in the cloth again and the doves will remove the character's face – this is another magic effect and can be saved against (DC 18).

The Guide:

Appears to be an androgynous human, dressed in a light cloak. The Guide will act friendly and helpful to adventurers until they attempt to escape the Castle.

Hit Dice: 5

Alignment: Neutral

AC: 12

Size: Medium

Number of Attacks: 2

Damage/Attack: 1d6 bludgeoning (attacking with wooden limbs)

The Spheres:

A series of three floating metal spheres. The spheres' will not let adventurers leave the immediate beach/field area without trying to drain their life.

Hit Dice: 8

Alignment: Evil

AC: 15

Size: Huge

Number of Attacks: 3 (1 each)

Damage/Attack: See below

Special Attacks: Each round, each sphere can drain 1 hit point of life from a player character. This can be saved against (Fort: DC 15)

Special Abilities: The Spheres also produce a high-pitched noise (The Sound of Space) out of the range of hearing for most creatures. Creatures with especially good hearing will be bothered by this noise – it will cause them to feel ill and prompt a Fortitude save (DC 15), failing that will leave the character at a disadvantage for saving against their hit points being drained for the next round.