The Unagugbaetu - The Planar Mites From Between The Cracks of Reality For Your Old School Space Opera

The Unagugbaetu
No Enc: 1d8 
Alignment : Chaotic 
Intelligence: Low 
Movement: 60' 
Armor Class: 4 
Hit Dice : 7 
Attacks: Bite 1d6 or claw 2d4 
Save: F7 
Morale: 10 
Psionic Strength : 3d4 
Hoard Class: XX 
XP: 1,550

Crawling across the threads that separated the myriad of realities are the Unagugbaetu the mites that feed upon the debris from a million shattered universes.
These creatures can break down anything that falls into their mandibles. These monster's flesh rolls with the very stuff of raw chaos and the energies of change.
These creature's claws can act as "swords of sharpness".Claws honed on the skulls of dead gods and the skeletons of  demons from before time of the last cycle of creation.
These monsters are used by the various Chaos goes as a final clean up crew once they have done toying with a plane within the local space time continuum. Their bite does 1d6 points of damage and is able to pierce even the flesh of gods. Wounds created by the monsters are ragged and tend not to heal right. They easily become infected and can often be rife with slimes, molds, and even worm like parasites that these things carry. These wounds must often be healed with magic, psychic healing or even super science treatments. All of these things are very expensive. 
These mad bastard children of chaos travel in packs of 1d8 monsters most of the time. But a forbidden variation of the summon monster spell or the rite of summon The Unagugbaetu will call one of these things from across the planes. 
These rites must always contain bile from these creatures or the monster will immediately attack the summoner. These monsters may be held at bay with the more powerful demons of chaos's blood. 
The flesh of these creatures roils with the raw stuff of chaos and the remains of these things will spread a contamination zone of some forty yards. Anyone caught within this zone must save vs death every 1d4 rounds or make a mutation check. This check must be made each time the victim is exposed to the demon beast's dead flesh.
There is a 25% chance of these bastards of chaos being immune to the effects of the artifacts of chaos. 
Clerics and mages of Law may have a ten percent chance of rebuking these demon beasts back beyond the vale from whence they come. Any failure will result in the monster trying to consume the cleric or wizard. 
Three times per day these creatures may move between the planes.Slowly they will phase away from the current space time continuum. During this time the beasts will only take half damage from most psychical attacks. Magic and psychic powers have full effects however. 
Three times per day the creatures can create darkness as a defense mechanism. 

The Unagugbaetu 
Swords and Wizardy version 

Armor Class: 6 

Hit Dice : 7

Attack Bonus : +8

Damage: 1d6 bite,1d4 

Number Appearing :1d8 

Saving Throw :10+
Special: See above 

Movement: 30

Morale:10