A trick has been discovered for making Mario invincible, which will likely make its way into some levels online before being patched out.
The discovery came from a fan of GameXplain, Abdul, who informed the team of it.
The video above shows how to replicate the glitch. You need to build a door on top of a spike pit, and upgrade Mario to a third form (like Fire Mario or Tanooki Mario). You then walk him onto the spikes, and send him through the door just before his post-damage invincibility period ends.
After this, Mario cannot be harmed by anything other than falling to his death.
You can try out Abdul’s level, which requires the glitch to pass, with this code: