After a quick post yesterday with some magic items to be found in the blood red cave, I though I would suggest some eerie, spine-chilling creatures for the cave system:

1. Hemaliths: Twisted rock-like creatures with veins of glowing red that pulse in time with the stream. They feed on the iron in the water and can meld into the cave walls, ambushing intruders with razor-sharp, crystallized limbs.
2. Crimson Eels: Translucent serpentine creatures that swim in the blood-red stream. They exude a hypnotic glow, luring prey into the water before constricting them with an acidic mucus.
3. Cavern Widows: Giant spider-like monstrosities whose webs stretch across the cave ceilings. Their abdomens are like molten glass, filled with an eerie red liquid that mirrors the stream below. The liquid bursts into flame when disturbed.
4. Stream Puppets: Skeletal figures half-submerged in the stream, animated by some ancient curse. Their movements are jerky, as though the stream itself is controlling them, and they emit horrifying, hollow laughter.
5. Sanguinite Golems: Massive, lumbering beasts formed of coagulated blood and minerals from the stream. They ooze a sticky red sludge as they move, and their touch causes blood to boil in living creatures.
6. Echo Banshees: Ghostly entities that float near the walls, mimicking the sounds of dripping water or distant whispers. When approached, they unleash a soul-piercing scream that can disorient or even paralyze.
7. Leech Vines: Parasitic, plant-like organisms that line the cave floor and walls. They lash out at passing creatures, siphoning blood to nourish themselves and the stream.

If there is any interest in me expanding on any of these, or perhaps create a backstory for the stream and the cave system, let me know. If there is enough interest I will write a whole adventure that you can use. All free of course.