(sorry about the bad paint cut&paste)
Said netherworm was nowhere to be found, and since i was playing an Oozemancer, the only things in my party should be mucus and bloated oozes anyways. This persists across zone changes, and i have found no way to interact with this "party member".
I think i eventually puzzled out what happened: Earlier i was in the illusory castle and on one of the floors, i suddenly got a message that said something like "Light of Revelation shines on Bloated Ooze revealing its true nature!". I didn't look too closely at it, mopped up the remaining enemies and picked up the loot. Amongst it was the artifact Light of Revelation.
I later took a look at it and i assume whatever enemy was holding it, attacked one of my Bloated Oozes, transformed it into a Giant Netherworm, and uuh... Not sure what happened then. Oozemancer summons are supposed to expire, but that probably got erased during the transformation.
So now i'm stuck with a dead horror in my player party. Which isn't much of a problem tbh, but maybe it counts against your wilder summon limit? (i haven't tested due to the random nature of ooze summoning)
