PlanKrab is a combo clone of Plankton and Mr. Krabs, hence his name. Created from both of their DNA, PlanKrab combines all the best attributes of the two. He possesses Plankton's genius-level intellect and Mr. Krabs' charisma, making him a true force to be reckoned with. The most devastating ability he has is his Persuasive Handshake, a handshake so firm and soothing that anyone who shakes hands with PlanKrab will temporarily be charmed by him to the point where they will do whatever he wants. PlanKrab is able to use this signature ability to easily take over businesses without any resistance against him.
Likewise, PlanKrab also combines the physical properties of Plankton and Krabs. His body build is similar to Mr. Krabs', but he is slimmer. His torso is green, but his arms and legs are red. His mouth and nose are identical to Mr. Krabs', but he only has one eye with two antennae, much like Plankton.
The twin PlanKrabs that are spawned are called green PlanKrab and red PlanKrab. Their personalities are no different from the original Mr. Krab and Plankton, respectively.
Biography
PlanKrab was created by Plankton by fusing his own DNA with Mr. Krabs' to create a combo clone that could easily infiltrate the Krusty Krab. Upon his creation, Plankton tries to relay his plan to PlanKrab, but PlanKrab stops him and announces that he already has his own plan, much to Plankton's delight, and goes off to the Krusty Krab. However, Plankton gets impatient and goes to the Krusty Krab himself to check on PlanKrab. There he finds that PlanKrab not only stole the Krabby Patty secret formula, but also took over the Krusty Krab and brainwashed SpongeBob and Squidward. Plankton asks how PlanKrab did all this, and PlanKrab explains that he has mastered the art of persuasion, by giving soothing handshakes that are so good that anyone who shakes hands with PlanKrab will do what he wants. Plankton finds the concept ridiculous at first, but then PlanKrab uses the Persuasive Handshake on Plankton and convinces him to give up the Chum Bucket. Having successfully acquired both restaurants, PlanKrab combines the two of them together to create the Krusty Bucket.
With both their restaurants stolen, Mr. Krabs and Plankton realize they're going to have to work together to defeat PlanKrab. They try out several plans to get their customers back, but PlanKrab thwarts them at every turn. Eventually, the two give up and decide to work for PlanKrab to stay afloat. They each ask for a management position, and PlanKrab happily makes them both managers... of the janitorial department. Krabs and Plankton are not happy about being reduced to custodians, and they begin fighting while trying to clean the toilets. PlanKrab goes in to stop the fighting, but when he sees Plankton and Krabs bicker over who defiled the restroom, it triggers a split inside him that causes his own Krabs side and Plankton side to tear apart. This results in PlanKrab splitting up into two smaller PlanKrabs who start fighting each other too. Mr. Krabs and Plankton see this as an opportunity, and they trick the PlanKrabs into shaking hands. The PlanKrabs are so soothed by their own Persuasive Handshakes that they melt into puddles and die, allowing Mr. Krabs and Plankton to take back their restaurants.
Trivia
PlanKrab is a portmanteau of Plankton and Mr. Krabs' names.
So far, PlanKrab and Burger-Beard are the only two villains in SpongeBob SquarePants besides Plankton himself who managed to steal the secret formula.
