The Zipps are a species from Dimension X, featured in the 1987-1996 series episode The Big Zipp Attack.
Zipps resemble small blobby dinosaurs in appearance, with lilac skin and small blue freckle-like dots. They have the power of flight, and typically levitate themselves to move around. They appear docile and friendly at first glance, and are highly affectionate towards those who are kind to them.
However, the species is highly harmful, which becomes obvious when they are exposed to metallic objects. Zipps have a ravenous appetite for any kind of metal - including metal combined with substances such as plastic - and will devour any metal they come across without regard for other life-forms. They also procreate at a dizzying rate, which makes them extremely hard to get rid of.
Zipps also have an unusual reaction to certain substances. When they eat anything with copper, the Zipp will suddenly become two. Chocolate has the reverse effect, but with the caveat that every reunited Zipp becomes larger and larger. And when a Zipp eats rigidium, it will shrink down (if large) or vanish from existence.