You see a bone capsule.
Notes
Apppears in the Ferumbras' Ascension Quest with Ragiaz.
Abilities
Unknown.
Damage Taken From Elements
Physical 
Death 
Holy 
Ice 
Fire
Energy
Earth
Drown
Location
Ferumbras' Ascension Quest quest area.
Behaviour
It doesn't move.
Strategy
Kill it as fast as possible to lower Ragiaz's healing.