Alhoon (summon)

Alhoon: These undead mind flayers are a rising power in the twisted politics of the Underdark.

Special abilities
An alhoon has damage reduction 15/+1 as well as 100% cold and electrical immunity. This creature also has most of the usual undead immunities, specifically to critical hits, disease, level drain, ability drain, mind-affecting spells, paralysis, poison, and sneak attacks. However, an alhoon does not have the usual undead immunity to death magic. (Probably a bug.) In addition, an alhoon has spell resistance 24 and +4 turn resistance.

The attacks of an alhoon penetrate damage reduction as a +2 weapon. In addition, this creature has use of psionic charm monster once per day, psionic inertial barrier and psionic mass concussion each twice per day, and psionic mind blast and psionic mind blast 10m radius each thrice per day.

A summoned alhoon is a level 19 wizard with the following spells prepared.