The Jellien clones look almost exactly like their Bikini Bottomite counterparts, except for a few traits. They have big, black eyes with white pupils and sharp teeth that are spaced from one another (even Jellien Patrick does not have Patrick's one tooth). Aside from those, the Jellien clones look like a mirror to their counterparts and can fool anyone into thinking they are normal citizens.
The Jellien clones are created when regular Jelliens, which the Evil Alien Jellyfish Overlord already made, attach themselves on top of the host's head, then squirt out a Jellien clone in its place. The Jelliens then take the real copies away where the Jellien Clones live out their lives.
After SpongeBob and Jellien Patrick give away Jelliens to everyone, the Jellien Bikini Bottomites start to take over. Like all Jelliens, they have big, black eyes and sharp teeth and talk in a slow manner. They spend most of their time at the Krusty Krab, ordering Krabby Patties without mayonnaise.
Behavior and weakness
The Jellien clones talk in a slow, monotone matter, much like how aliens would talk. Some of them, mainly Jellien Squidward, would sometimes end their sentence with a "RAH"-like sound. They even seem to act like their real counterparts, such as eating Krabby Patties. However, when someone mentions mayonnaise, they act extremely aggressive and attack on sight.
They also seem to hiss and point at anyone that mentions the condiment. This is because mayonnaise is their one and only weakness. If touched by mayonnaise, the Jellien clone will melt into a pool of green slime and the bodies, which they took over, will wake up.
While lacking any ability to create Jellien clones, they would attack in droves and fight to death for the sake of the Overlord's safety, as seen when they surround and try to attack SpongeBob and Sandy, even if they got eventually killed off by both of them with mayonnaise.
The Jellien Bikini Bottomites' real behavior when there are no ordinary lifeforms around is much different when compared to their real copies. They mainly act like mindless zombies, which, of course, are made to serve the Overlord. They also seem to enjoy hissing, especially when someone mentions mayonnaise. They also appear to walk very slowly like zombies but can also run very fast, as they were chasing SpongeBob out of the Krusty Krab.
Given that they cannot create clones unlike Jellien Jellyfish, they serve as secondary Jelliens.