Ectoplasm

Ectoplasm was an insubstantial substance that resulted from the use of psionics. It originated from the Astral Plane.

Description
Ectoplasm took various forms, depending on how it was manifested. In its original form, it could appear smoky, diaphanous, or as finely spun strands. Things made of it were visible only as wispy outlines, appearing ghost-like. Alternatively, in liquid form, it could be a goo or slime that was translucent and ephemeral. There were also semi-solid and solidified forms that were partially translucent and rippling. A crystalline form was also possible.

It sometimes shimmered if it carried or resulted from a psionic effect.

Properties
Ectoplasm was completely inert but unstable ectoplasm could be created that dissipated explosively, initially producing "hellish" flames but later different kinds of energy: fire, cold, electricity, or sonic. It was composed of particles but could be drawn into writhing strands.

Solid ectoplasm could not be bypassed by ethereal or incorporeal creatures.

Creation
When a part of the medium of the Astral Plane was drawn into the Material Plane, it became raw ectoplasm. The manifestation of many psionic powers could, if not suppressed, produced a material display of ectoplasm as a seepage from the Astral Plane. The target or area became slicked or sheened with shimmering ectoplasmic goo, which evaporated after several seconds. A shimmering ectoplasmic film was also the effect of a dimensional anchor power.

Powers of the metacreativity discipline pulled raw ectoplasm and other matter from the Astral Plane for a psionics-user such as a shaper to fashion into objects and even pseudo-living constructs of their choosing. Such things were solid or semi-solid and as durable as normal matter, being held together by psionic energy for their duration. When ended or dispelled, they disappeared, leaving a few drops of liquid ectoplasm or a thin film of glistening ectoplasm that swiftly evaporated.

The ectoplasmic form power turned a being and what they wore or carried into ectoplasm. Originally, they could pass through solid matter like it wasn't there. Later, they became almost insubstantial and couldn't manipulate the world around them. They could only pass obstacles if there were small gaps, and couldn't pass through water.

The dismiss ectoplasm power caused all affected ectoplasmic objects and creatures that could not resist to dissipate to their constituent ectoplasm and subsequently evaporate in several seconds. A being in ectoplasmic form had a 50% chance of being obliterated or transported to a random spot in the Astral Plane.

Scholarship
"Sophisticated" psions understood that the sheen left as material display was ectoplasmic from the Astral Plane.