Onboard the Garogan Space Station, White Garoga presents Baron Garoga with a gift, a tiny creature from Planet Jellarl named Jellar. He insists that Jellar is impervious to Zone Fighter's Proton Beam. The creature is loaded into a Terror-Beast Missile and launched towards Earth. Hikaru and Hotaru spot the missile flying above, and track it down. However, when they get there, they find two Garogas defending the capsule. After a short fight, the Garogas are repelled, and Hikaru and Hotaru gain control of the capsule. The Garogas return, and state that they will release Akira, who they are holding hostage, in exchange for the capsule. The Zone Family agrees to this exchange, but a scuffle breaks out between the Peacelandians and the Garogas. During the fight, the capsule is broken, releasing Jellar. Hikaru transforms into Zone Fighter, but quickly gets beaten down, and true to form, Jellar is resistant against Zone's Proton Beam. Godzilla is called into battle, and helps Zone Fighter back up. He then runs towards Jellar, and rips one of his tentacles off. This tentacle grows into a new monster - Kastam-Jellar! The two heroes, now evenly matched, fight bravely on, and Zone Fighter recieves extra energy from Smokey, which is being piloted by Zone Angel and Zone Junior. Jellar and Kastam-Jellar are soon defeated.
- Jellar is impervious to Zone Fighter's Proton Beam.
- Like starfish and some species of octopus, Jellar can regrow disembodied parts of himself into a completely new organism. This is how Kastam-Jellar was born.
- Jellar can expel an acidic mist from his arms.
- Jellar can fly.
- Jellar, like Gigan, is one of the few non-manufactured Kaiju used by the Garogas. However, he is referred to as a Terror-Beast in his subtitle, even though he was obtained from Planet Jellarl as a natural organism.