There is one in the epic section of the 3.5 srd, and it is nasty. I don't think it is the same as the alienist one.
CREATING A PSEUDONATURAL CREATURE
“Pseudonatural” is a template that can be added to any corporeal creature (referred to hereafter as the base creature).
Size and Type: The creature’s type changes to outsider (extraplanar). Do not recalculate base attack bonus, saves, or skill points. Size is unchanged.
HD: A pseudonatural creature always has maximum hit points.
Speed: A pseudonatural creature’s speed doubles, for all movement types.
AC: Pseudonatural creatures gain a +35 natural armor bonus. If the creature already has an armor bonus, use whichever is better.
Attack/Full Attack: A pseudonatural creature substitutes tentacle rake attacks for its melee attacks while in pseudonatural form. These tentacle attacks always use the creature’s best attack bonus. It also gains additional tentacle rake attacks (also at its best attack bonus) as noted on the table below.
Damage: Tentacle rakes from a pseudonatural creature deal Damage equal to 2d8 + Str modifier.
Special Attacks: A pseudonatural creature retains all the special attacks of the base creature and also gains the following.
Constant Insight (Su): The creature makes all its attacks with a +15 insight bonus. The creature is not affected by the miss chance that applies to attacks against a concealed target.
Improved Grab (Ex): If the creature hits an opponent smaller than it with a tentacle, it deals normal Damage and attempts to start a grapple as a free action without provoking an attack of opportunity.
Rotting Constriction (Ex): Once the creature has hold of an opponent, each successful grapple check it makes during subsequent rounds permanently drains 2d4 points of Constitution. At the same time, the creature regains 10 lost hit points.
Spell-Like Abilities: At will—blur, dimension door, shield, unhallow. Caster level 20th. The DCs are Charisma-based.
Special Qualities: A pseudonatural creature retains all the special qualities of the base creature and also gains the following.
• Electricity and acid resistance of a varying amount related to its Hit Dice (see the table below). If the creature already possesses such resistance, use whichever is better.
• Damage reduction of a varying amount related to its Hit Dice (see the table below). If the creature already possesses Damage reduction, use whichever is better.
• Spell resistance equal to the creature’s HD x5. If the creature already possesses spell resistance, use whichever is higher.
• One extra tentacle rake attack (the creature can use another of its many tentacles to attack at no penalty while in pseudonatural form) for each 4 HD the creature has.
• A pseudonatural creature’s natural weapons are treated as epic for the purpose of overcoming damage reduction.
Hit Dice Electricity and Acid Resistance Damage Reduction Extra Tentacle Rake Attacks
1–3 15 5/epic 1
4–7 20 5/epic 2
8–11 25 10/epic 3
12–15 30 10/epic 4
16–19 35 15/epic 5
21–24 40 15/epic 6
each 4 more HD +5 15/epic +1
If the creature already has one or more of these special qualities, use the better value.
Alternate Form (Su): At will, a pseudonatural creature can take the form of a grotesque, tentacled mass (or another appropriately gruesome form), but all its abilities remain unchanged despite the alien appearance. Changing shape is a standard action. Other creatures receive a –1 morale penalty on their attack rolls against pseudonatural creatures in this alternate form.
Saves: Same as the base creature.
Abilities: Increase from the base creature as follows: Str +22, Con +10, Dex +10, Wisdom +10, Intelligence at least 3.
Skills: Same as the base creature.
Feats: Same as the base creature.
Climate/Terrain: Any land and underground.
Organization: Same as the base creature.
Challenge Rating: Up to 6 HD, as base creature +16; 7 HD to 15 HD, as base creature +13; 16+ HD, as base creature +10
Treasure: Same as the base creature.
Alignment: Same as base creature.
Advancement: Same as the base creature.
