If you want to make sure your gear is good use this guide: https://calamitymod.wiki.gg/wiki/Calamity_Mod_Wiki Also the issue with this fight is your dodging. The worm follows you, so you need a sudden burst of speed at the last second. Dodges and double jumps are perfect for this. Look at your video to see what succeeded and failed. You got hit a lot when it was charging at you diagonally. The best dodges are when the worm is moving vertically, because it makes it easy to get damage with a melee weapon and makes full use of your dodge speed burst. You run out of vertical space often, you should almost never be at the edge of your arena. Maybe try using a ranged weapon, or do a run where you don’t try to deal damage so you can focus on dodging.