The International Justice League of Super Acquaintances, or I.J.L.S.A for short, is a group/league of superhero sidekicks who originally fought alongside Mermaid Man. The league consists of The Quickster, Captain Magma, the Elastic Waistband, and Miss Appear. They fought the Dirty Bubble, Man Ray, and Barnacle Man in the episode "Mermaid Man and Barnacle Boy V." They later appear in "The Bad Guy Club for Villains."
The International Justice League of Super Acquaintances is run and founded by Mermaid Man. He is the main leader but not the chief, similar to Superman's leadership and Batman's secondary leadership with the Justice League and Super Friends. Unlike Superman and Batman, he orders pizza to his hero allies at the table instead of announcing brief missions.
- Able to throw waterballs
- Use system targeting
- Weakness: Falling on his back.
The Quickster has the uncanny ability to run at record speeds. This super speed was ultimately SpongeBob's downfall when he had to become the Quickster, as he was running around in a circle after getting hit with Captain Magma's eruption by accident, until he eventually melted and/or disintegrated.
He is a parody of the DC Comics superhero Flash and the Marvel Comics superhero Quicksilver with the same lightning bolt logo. The eagle wings on the side of his mask also make him resemble the Marvel Comics superhero Captain America the golden age Flash, the Marvel Comics superhero Whizzer, and Hermes, a Greek god associated with speed and good luck, who served as a messenger to Zeus. His outfit resembles the costume worn by the DC Comics superhero Impulse. The eagle wings on the side of his boots also make him resemble the Marvel Comics superhero Namor, in that he has two tiny wings on both his ankles, which allows him the ability to fly, and Hermes, on both sides of each of his sandals called the Talaria, which also give him the ability to fly.
- Weakness: He can create a rut if he runs in a close formation and be trapped in it.
Captain Magma wears a miniature volcano on his head. By shouting "Krakatoa!," he can erupt a blast of sizzling lava from said volcano. He can also use his volcano as sort of a makeshift jetpack. Captain Magma is extremely weak to Mermaid Man's water balls, as one of these water balls, misfired, hit Squidward, in Captain Magma costume, and quenched him.
In "The Bad Guy Club for Villains", he is called Professor Magma.
- Weakness: He can be quenched by a water ball or anything attributed to water, despite living underwater.
The Elastic Waistband
The Elastic Waistband can stretch his body parts extremely long. He has a limit, however; when Patrick as the Elastic Waistband tried to save the Quickster, who was running around in a circle, his hands got caught, and his arms got overstretched, spelling his defeat.
- Weakness: He will turn into a long piece of rubber string once he is stuck in a spinner.
The only female member of the group, similar to Wonder Woman of the Justice League and Super Friends. Miss Appear can turn invisible at will. However, she is still solid; Sandy, as Miss Appear, turned invisible, then got hit by a boat and hurled off a cliff. Miss Appear is a parody of Invisible Woman from Fantastic Four, but in "The Bad Guy Club for Villains," she seems to resemble Wonder Woman more, in both looks and personality.
- Weakness: Anything dangerous cannot see her invisibly.
The IJLSA vs. EVIL
The battle between the International Justice League of Super Acquaintances (Mermaid Man, the Quickster (SpongeBob), Captain Magma (Squidward), The Elastic Waistband (Patrick), and Miss Appear (Sandy) and Every Villain Is Lemons (Barnacle Man, The Dirty Bubble, and Man Ray) was rather pathetic. Captain Magma erupted a burst of lava that hit the Quickster. The Quickster began running around in circles in an attempt to get the lava off. The Elastic Waistband attempted to save the Quickster with his hands, but they got caught; the arms overstretched, and The Elastic Waistband got hurled into the air, and landed on the ground, his arms in a tangled heap on top of him. Mermaid Man tried to cool off the Quickster by shooting a water ball, but instead hit Captain Magma with it.
It was all up to Miss Appear. She turned invisible and tried to sneak over to EVIL to combat them unseen. However, she got hit by a boatmobile and fell off a cliff. After 5 seconds, Mermaid Man then fell over anyways, and EVIL won unnecessarily without having to do anything (although Barnacle Boy rejoined Mermaid Man's team once again).
In the episode "Mermaid Man and Barnacle Boy V," SpongeBob, Patrick, Squidward, and Sandy put on the costumes of The Quickster, The Elastic Waistband, Captain Magma, and Miss Appear respectively in order to stop Every Villain Is Lemons (EVIL for short).
The original International Justice League of Super Acquaintances appears in the episode "The Bad Guy Club for Villains."
- The name is an obvious nod to Justice League of America from DC Comics, with some of the most famous members being Superman, Batman, Flash, Green Lantern, Wonder Woman, Aquaman, and Cyborg.
- As well as this, the name is also similar to a spin-off group of the Justice League of America called Justice League International.
- On the I.J.L.S.A. Lunchbox, part of the name has the word "Acquaintances" is misspelled as "Aquaintances." However, this can be interpreted as being a pun on the members of the I.J.L.S.A.'s aquatic nature.
- In "The Bad Guy Club for Villains," the group is said to be called the "International Justice Lodge of Super Acquaintances."
- The group is also a subsidiary of ViacomCBS due to Nickelodeon being owned by ViacomCBS' predecessor at the time, the original Viacom.