The Jellion Clones look almost exactly the same as their Bikini Bottomites counterparts, except for a few traits. They have big, black eyes with white pupils and sharp teeth that are spaced from one another (even Jellion Patrick doesn't have Patrick's one tooth). Aside from those, the Jellion Clones look like a mirror to their counterparts and can fool anyone into thinking they are normal citizens.
The Jellion Clones are created when regular Jellions, which the Evil Alien Jellyfish Overlord already made, attach themselves on top of the host's head, then squirt out a Jellion Clone in its place. The Jellions then take the real copies away where the Jellion Clones live out their lives.
The Jellion clones talk in a slow, monotone matter much like how aliens would talk. Some of them, mainly Jellion 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 Jellion clone will melt into a pool of green slime and the bodies which they took over will wake up.