Though his creation was not shown like Jellien Squidward and Jellien Patrick's, it could be assumed that Jellien Mr. Krabs was created when SpongeBob helped Jellien Patrick deliver the caught Jelliens to all of their friends. He makes his first appearance after a guy who was not a Jellien orders a Krabby Patty with mayonnaise. Jellien Mr. Krabs then tells the guy that they do not serve mayo, then places a Jellien on the guy's head. After knowing SpongeBob had discovered the Evil Alien Jellien Overlord, Jellien Mr. Krabs attempts to plant a Jellien, to no success. He then tells SpongeBob to go home and get some rest, actually hoping that the other Jellien Clones will get SpongeBob and turn him into a Jellien. He then discovers SpongeBob and Sandy trying to sneak in with fake eyes and shouts out "IMPOSTORS!," alerting the other Jelliens to attack the two. He is eventually defeated when SpongeBob squirts him with mayonnaise.
Next to the Evil Alien Jellyfish Overlord, Jellien Mr. Krabs actually acts more of a leader to the other Jellien clones. Unlike the real Mr. Krabs, Jellien Mr. Krabs has more of an obsession to help create other Jelliens rather than to receive any money. He also seems to be more in a good, less serious mood unlike the other Jellien clones especially Jellien Patrick.
"I am sorry, valued customer. We're currently out of the condiment you call mayonnaise. Please accept this free jellyfish hat instead. Thank you, come again!"
"You look tired, SpongeBob! Why don't you go home and take a nap?"
In all the scenes Jellien Krabs is shown in, he tends to have a common pose, and does not move much when he is in the Krusty Krab.
When Jellien Krabs is in his office before the normal fish asks for one Krabby Patty with mayonnaise, it is unknown what Jellien Krabs does, considering the fact that Jelliens do not know he is a cheapskate and counts money all day, because Jelliens do not use money.
He replaced Mr. Krabs as the manager of the Krusty Krab temporarily.