Ankhegs.
A type of huge monster living in the Underdark!
These lifeforms were quite huge and were somewhat similar to octopi, but looked like huge insects.
Ankhegs had sixteen limbs.
But these limbs were really different from those of an octopus.
Ankheg limbs were very hard and the each had a tip shaped like a sharp spiral. They were very good at digging holes through the mountain.
There weren't many of them and they were rather averse to moving around.
According to the Pearl Tower's scholars, more than 60% of the caves in the Underdark weren't formed naturally but were in fact the result of active Ankhegs.
Ankhegs had very sharp awareness. Their caves would rarely collapse because they could choose places where the earth was relatively stable to make their path.
'I didn't expect that even Ankhegs were subdued by Black Dragon Clarke!'