You will need two players for this trick. Go into Forge mode. Create an Armor Lock armor ability, then drop it on player two. Next, create another Armor Lock ability and press B. Go to delete all of these from the map. Click it, and hover over "Yes". Have the player two go into Armor Lock. While he is in Armor Lock, select "Yes" at the "Delete all of these from map" message. Player two will now be invincible, and can move around in permanent Armor Lock. You can still use other equipment, such as Evade.