The details are a little fuzzy from what I’ve gathered. For those that need a little catching up, Vader lost his legs in a battle with Obi-One Kenobi. I found it a little unclear as to how his legs are lost exactly, before falling into the volcano by a saber cut or from falling into it. I’ve to do a bit more research on this.
“Ani” tried to show how much more powerful than Obi-Wan he was and tried to jump over him during their last battle in Episode 3. Kenobi, after warning him not to try it, took the opening and sliced off his legs. Skywalker landed next to lava and slowly started sliding in, the heat making him catch on fire in the process as he closed distance.
To this day, my family (started by my father) mockingly quote Anakin’s “You don’t know my power!” when we are about to do something silly/stupid.
That’s an awesome way to drive home the point!
“You underestimate my power!”* (Anakin Skywalker)