Mr. Jenkins is a truck driver. His ex-wife is Mable Jenkins.
When Plankton insults Taylor in "20,000 Patties Under the Sea," his ex-wife takes offense and says, "Hey, you can't talk to my son that way," so Plankton fires back at her. Then he came out and says, "You can't talk about my wife that way! What do you think this is?" When Plankton calls him fat, his mother comes out in his defense, and Plankton tells her that she belongs in a box floating down the river, and she replies, "You're probably right."
When Plankton turns to leave, Mr. Jenkins and his family begin to throw rocks at him and his submarine (the fist on the Chum Bucket). When they run out, SpongeBob SquarePants and Patrick Star sell them Krabby Patties that Patrick left unattended, therefore burned, in their sub (the one they found by their houses).
In "The Gift of Gum," the wheel of his truck, Old Blue, gets stuck in the gum that Patrick gives SpongeBob in celebration of Best Friend Day.
Mr. Jenkins is a green fish that has a red cap and a red tiled shirt.