Juiblex, the Faceless Demon Lord, a nauseating and disgusting pile of sentient, poisonous slime. He can spread himself in a pool or rise up in a column, but his filthy and loathsome form will always evidence several glaring red eyes. The more you study these high-powered demons, the more fun they seem.
Psionic Random Encounters - with Demons
The use of psionics, or psionic-like spell powers, will attract the attention of psionically-powered creatures. Think of it as "a disturbance in the force".
The 1e DMG recommends (on pg. 182) that if a player has used psionic or psionic-like powers in the last turn, if a random encounter turns up, there is a 25% chance that random encounter will be a psionic monster.
According to the table, there is a 19% chance that this random psionic creature will be a demon or a devil. Thus, if psionic powers are used, there is a roughly 5% chance that the next random encounter will be with a demon or devil. Ha, now that is a pretty sweet stat.
Of course, if you are really itching to encounter one of these things, just start screaming out its name while in an ethereal state -- Gygax recommends a base 5% chance that the named demon will pay attention to the summons.
Spells Resembling Psionic Powers
astral spell, augury, blink, charm (any), clairaudience, clairvoyance, cure (any), detect (any), dimension door, enlarge, ESP, feather fall, feign death, heal, heat metal, hypnotism, invisibility (any), know alignment, levitation, plane shift, polymorph (any) remove curse, shape change, stone tell, tele- (any), temporal statis.
Basically, any power that taps into the spirit/astral plane to find information or create some physical effect is emulating psionics. I would think that gate and summons spells would also fall into that category.
This is just like Sauron, with his big flaming eyeball, being immediately able to see anytime his ring was used. That ring was like a ring of etherealness, allowing Frodo to see things also in the ethereal state, and of course, to be seen by things in the ethereal state. "Popping into" the ethereal state gets the attention of things who can see into that state.
In other words: BEWARE! When you use these astral powers, you call the attention of astral beings.
Back to Juiblex specifically:
HD: 88 hp
attacks: lashing blow (4-40 dam.)
magic resistance: 65% (+2 weapons or better weapons to hit)
Psionic Ability: 225
circle of darkness (15' rad)
circle of cold (10' rad)
regenerate 2 hp per round
invisibility (10' rad)
telekinesis (1500 pounds)
putrify food & water
speak with monsters
1x per day:
gate (1-4 type 2 demons)