Wherever he is...
I think a Vizier's Turban got him.
Alright, here's my take on the VT...
Vizier's Turban
Tiny Aberration (Symbiont)
Hit Dice: 1d8 (4 hp)
Initiative: +2
Speed: 20 ft. (4 squares)
Armor Class: 15 (+2 size, +2 Dex, +1 natural), touch 14, flat-footed 13
Base Attack/Grapple: +0/-10
Attack: —
Full Attack: —
Space/Reach: 2-1/2 ft./0 ft.
Special Attacks: Symbiotic spellcasting
Special Qualities: Darkvision 60 ft., spell resistance 10, symbiont traits, telepathy
Saves: Fort +0, Ref +2, Will +5
Abilities: Str 6, Dex 15, Con 11, Int 18, Wis 17, Cha 16, Ego x
Skills: 6
Feats: 1
Environment: Any
Organization: Solitary
Challenge Rating: 1 (singly) or host +1 (when worn)
Treasure: None
Alignment: Any
Advancement: None
Level Adjustment: —
Symbiotic Spellcasting (Ex); A creature with an attached vizier's turban can transfer up to 10 points of its Constitution to the vizier's turban each day. For each point of Constitution transferred, the host gains 1 point of spell resistance and one additional spell level. These spell levels can be used to cast additional spells. Spontaneous spellcasters gain additional spell slots totaling a level equal to the sacrificed Constitution. Spellcasters who must prepare their spells may memorize additional spells totaling a level equal to the sacrificed Constitution. The spell levels may be split in any combination, but a single spell slot/prepared spell cannot exceed 5th-level. A 0-level spell counts as a half-level for these purposes. Thus, a sorcerer sacrificing 5 points of Constitution could gain a single 5th-level spell slot, a 4th-level and 1st-level spell slot, a 3rd-level and 2nd-level spell slot, and so forth. A wizard transferring 5 points of Constitution to its attached turban could prepare an additonal 5th-level spell, a 4th-level and 1st-level spell, a 3rd-level and 2nd-level spell, and so forth.
Transferred Constitution is not Constitution damage or drain, and thus cannot be restored by spells such as restoration or heal. The Constitution immediately returns to the host 24 hours later, but cannot be regained in any other way, even if the attached vizier's turban is slain.
The transferred Constitution reduces the host's hit points, Fortitude save, and Constitution-based skill modifiers and save DCs. Likewise, the vizier's turban gains an increase to its hit points, Fortitude save, and Constitution-based skill modifiers and save DCs.
Telepathy (Su): A spellwurm can communicate telepathically with its host, if its host has a language.
I chose not to include the "transfer vitality back" bit, but if I were going to do so, I'd just modify the above ability to allow a vizier's turban to transfer back a number of Constitution points up to what was originally transferred, and require the spellcaster to sacrifice an equivalent number of spell levels to pay for it.