The Electric Ixupi is best described as a bunch of lightning bolts in the form of a humanoid form. It does have a menacing looking face, whose features are highlighted by lightening bolts.
Known hiding spots
Most encouters with the Electric Ixupi happen in the top floor of the museum. It is known to strike from a light in the Planetarium. Another location the Electric Ixupi is known to hide is in the Electric Chair Exhibit, in the Man's Inhumanity to Man room. This second location can actually be controlled, since the chair is not active when you first enter the room. The Electric Ixupi has one other hiding spot, which is the generator in the Power room.
Signs of Ixupi
The appearance of the Electric Ixupi is usually accompanied by the sound of exposed wires crackling with power. The only place this is out of place is in the Planetarium, so it will be difficult to tell when an attack is coming.
Capturing the Electric Ixupi is the final task to be done. This is made more difficult by the fact that only one half of its vessel can be found in a random location. The other half is the reward for solving the riddle chain. Afterwords, the Electric Ixupi can be found in the generator in the power room.
Loose in the world
If the Electric Ixupi had been able to get loose, the range of hiding spots is astronomical. Human kind had become dependent on electricity, and such, the Electric Ixupi would have a field day killing people.