Very few cats are naturally immune to this affliction. Greeblingz are believed to be non-visible entities, and some authorities have linked them to UFO sightings or feel that they may be diminutive beings from another dimension or a parallel universe. Cats suffering from greeblingz typically have wild-eyed expressions, and seem to be possessed with a need to eradicate greeblingz whenever they are sighted. Anti-epileptics are ineffective as the condition appears unrelated to other forms of seizure. Avoid getting in the way of cat engaged in pursuing greeblingz.
Attacks usually subside spontaneously, perhaps as greeblingz return to their own dimension.
These irritating creatures are not visible to human eyes, but no doubt the superior sight and hearing of cats enables them to see them.