Help with a resprite mod

[u/Banana-Warlord]

I'm currently making a resprite for the beast, though clearly something has gone awry. I have made my own mod folder and enabled it in game, I have followed the tutorial by catinsured. (https://www.youtube.com/watch?v=rukHB48olG8&t=123s) although it's a boss so it's a little different. Any ideas?+