A running gag is a joke used a lot in a series. TARS has a few.
Blue Kirby took my "Insert Item Here" Edit
Due to Blue Kirby taking pieces, some people like to joke that Blue Kirby took their "item they lost."
Sun and the Earth Edit
This joke spawns from Final Destination in Smash Wii U. In that stage, the sun and the earth are unrealisticaly close to each other, which is probabaly why the fighters are in space. This joke is used several times in TARS.
My weakness is my own special weapon. Edit
This joke comes from Metal Man, who is weak to his own special weapon. Characters like to insult others by saying they are weak to their own special weapon. Some villains in long comics have a weakness to their own special weapon, like The New Mayor.
My Weakness is the Metal Blade Edit
A recurring joke in the series is where when a character says Defenitaly Not, they actually mean Defenitaly. The Shadow Star is the most common culprit of this.