Correction on spawn conditions. This is a normal named in that you kill the placeholder and have a chance at named on next spawn cycle unlike what the previous comment states.
Placeholder is in the far back section, pher is a drachnid, the type of drachnid can variate. It will sometimes spawn as "a crystal purifier" or "a drachnid retainer." Location is -373, +491, -562.
The spawn is strange in that the placeholder/named will sometimes spawn in the center of the ice platform and then path over to underneath the web or sometimes spawn directly underneath the web.
Mob is NOT considered undead for any Paladins out there.