ToME: the Tales of Maj'Eyal

As a reaver, I've seen this from both of the talents that spawn carrion worms: they can spawn on top of mobs. The mob is then invisible, unattackable and untargetable until the worm moves from the space (or dies). When that happens, the mob is still untargetable and invisible until it moves, but you...

This also happens with the grubs spawned by the corruption/rot talents infestation and worm rot. I often end up under my own rot grubs (or worse, with foes under them), and become unable to target whatever is under them. Even once the grub self destructs, the character's icon will not show up until ...