Tentacles of the deep

This is a tale specific to dwarven kind. Because of their lust for gold and their hardheadedness to never back down. There is a tale that warns dwarven children of the dangers of some tentacled creatures that would be incredibly dangerous if encountered.
These creatures they are talking about are grick grell and other aborations like that. Though they are usually told with a greed in mind for the deep and not knowing when to stop.

Historical Basis

A thousand years the king of mjolnar who goes by the name of: King duram. The king came to power in an era of prosperity for the dwarves. He let that prosperity get to his head and thought it was because of him the dwarfs thrived and ordered the dwarves to dig deeper for more riches than there ever have seen before. As the miners dug deeper and deeper the ground became thougher and tougher, however they still continued. The consequences of this was that the miners had unleased creatures that should not reach the surface. They were aborations which they had never seen before. These creatures slaughtered the dwarves moved through the dwarven tunnels and attacked Mjolnar. The forces of Mjolnar weren't battle ready however because of their numbers was finally able subude them after a big loss on their side.

Spread

It is pretty well known for dwarves however outside of that it is unknown.

In Art

There are a couple of dwarven songs about it, however it is usually considered a myth to warn children of the dangers of the deep, but not anything that actually happened.