"There is hope. Hope is alive in us. Because today, we will make a stand against evil. Today, we will plant our feet firm for justice. Today we will squat over our fallen enemies. Because today is a new day. Today is ... Leg Day."
"Leg Day" is the second episode of Season 3 of Teen Titans Go! and the one hundred and sixth episode overall. It first aired on 6 August 2015 on Cartoon Network.
After being defeated due to poor leg strength, Raven and the Titans work out their lower bodies and become the League of Legs.
A pelican eats a crab while Robin, Cyborg, Starfire, and Beast Boy work out their upper body at Titans Tower. Beast Boy invites Raven to join them, but she says that it's Leg Day only for Robin to ridicule her. The Titans begin kissing their muscles when the crime alert blares. They head to Jump City and find it under siege by robot walkers. One raises its leg and threatens to crush the Titans, but they use their arm muscles to lift the leg. Raven tells the Titans that they need to lift with their legs, but the Titans refuse to listen to her and they are crushed by the robot.
That night, the Titans lament their loss and the failure of their upper body strength. Raven makes an inspiring speech that they will defeat evil as today is Leg Day and transforms into Lady Legasus much to Beast Boy's excitement. Robin tells Lady Legasus that the threat is bigger than her two legs and she says she's going to need their legs. Robin and Starfire believe their legs are too weak to be of any help, but Lady Legasus announces that she will train them.
Lady Legasus takes the Titans to a stadium and train them until their leg muscles are defined. She rechristens them as the League of Legs and gives them new identities: Cyborg becomes Thunder Thighs, Starfire becomes the Incredible Quad, Beast Boy becomes the Calf, and Robin is named Captain Cankle. At Legasus Headquarters, the League of Legs coordinate an attack on the robots. The Incredible Quad notes that the robots' new positioning indicates that reinforcements are on the way and Captain Cankle stresses that they need a plan to take the robots out. Lady Legasus proposes a frontal assault as the robots' foundation is vulnerable since most of them are protecting the upper levels of the command center. Captain Cankle agrees with the plan and the Legasus Headquarters rockets to Jump City. There, the League of Legs take down most of the robots. One threatens to crush Captain Cankle, but Lady Legasus pushes him out of the way and raises the leg with her legs. She is joined by the rest of the League of Legs and together they use their legs to throw the robot into the air where it explodes.
The League of Legs celebrate their victory, but Lady Legasus claims that they have to disband as their legs are too powerful to be wielded. She says that they have to sit on the couch and watch TV so that their legs can waste away and reform the Teen Titans as she transforms back into Raven. The Calf asks to use their legs one last time and Raven agrees and becomes Lady Legasus again. A pedestrian notices the League of Legs and sings "Look at Them Legs" in response to their legs.
The way the Titans' new aliases are introduced references how the Sailor Soldiers/Sailor Guardians are introduced in the Sailor Moon series, with Robin even blushing after his transformation like the Sailor Soldiers/Guardians would.