The Jamminga are unique to the Zoids: Wild ZERO anime series.
First seen in episode 1, the Jamminga seem to be Zombie-like Zoids that roam uninhabited areas.
They are small, slightly larger than a car, and Raptor-esq in appearance. They are seen covered in rust and with slow, rough movement. They lack any armour or weapons.
The Jamminga are an annoyance to the various militaries of the Republic and Empire, and also prevent civilians from leaving established towns/cities.
Characters like Buzz Cunningham use their knowledge as couriers to avoid the Jamminga and explore old ruins for valuable technology left from the 21st century.
The Jamminga first appeared on Earth when the Zi-Forming project was attempted prior to the start of the series.
The failure of the Zi-Forming is known as the "Zoids Crisis", and was initially seeded by "Regeneration Cubes". In the series, the failure of these cubes potentially results in a "Time Vortex" and the appearance of Jamminga.
It is known that Sally's pendant is related to the Regeneration Cubes, and that Leo's father was researching the Time Vortex. Additionally, Frank Land and Walter Borman are both involved extensively with the Zi-Forming research and technology.