That is a cool creature!
I can't say much balance wise. I like the Skeleton Host ability because it gives variation to the ooze. Adding any persistent fire damage to attacks is nasty but cool. It takes more damage but becomes more dangerous.
What I would maybe add is a 1 or 2 action ability to leave the skeleton behind... an escape action against prepared party with maces in all hands:
The ooze steps or strides and loses its skeleton host in its starting squares. It loses any speed, temp HP and natural attacks but also loses the bludgeoning weakness. The squares with the skeleton count as difficult terrain.
I want to second masda_gib's suggestion. I also think there should be something where after an amount of bludgeoning damage the skeleton is effectively destroyed. Maybe also have each use of bone spur reduce the hp the skeleton has.
I want to second masda_gib's suggestion. I also think there should be something where after an amount of bludgeoning damage the skeleton is effectively destroyed. Maybe also have each use of bone spur reduce the hp the skeleton has.
I thought about that too but thought that such a "at half HP, the skeleton is destroyed and the weakness is lost" ability would add too much complexitivity without much gain aside from "realism"(TM).
It would basically just be an automatic usage of the ability I suggested. :) Yeah, maybe it could be added as a reaction with trigger "the creature takes damage which brings it under half HP". ...but that might be too many abilities.
Maybe it also needs a limit for the level of the skeleton that is absorbed. Since the ooze gets its natural attacks, absorbing a level 18 skeleton gets it some hefty attacks.
I would limit it to level 10 (same as the ooze) or add some rules for adjusting the natural attacks (e.g. -2 damage per level above 10).