GeckoLib is needed

The mod is possessed by an entity that... - a piano??

Partially... because a monster is stuck in it... how? you'll see a little lower... but for now I'll tell you about the mod: a creature that attacks you in caves! climbs walls (how?...) breaks doors (horror scary!) and is very strong!

Lore:

Once upon a time, residents were disappearing in the forest near the village. No one knew what it was.... But one day it came out of the forest. An entity similar to the player but with dark red eyes. Residents hid and golems could not cope with it. But during the day the creature returned to the forest. All the residents were moving from the village and collecting things. But one resident had a piano. He wanted to move it but saw red eyes in the dark and ran away. The monster approached the piano. It seemed there was meat there. The monster climbed inside but the lid slammed shut and he could not get out. He stayed there to live but could still hunt...

Credits to: TheOman (Animations and the creation of the mod, although the model was not made by him)