This boss took around 2000 lines of code to make this guy. His behavior heavily has similarities to the Bowser in Darkonius's DA:E episode. With a hefty amount of customibility in his lua file, you can just recreate the Bowser from SMB1, SMB3, and maybe other Mario games. The flamethrower attack is requested by MegaDood.
Credits:
Mega Man: The Sequel Wars OST - EX Midboss (YM2612) - Woodfrog
Bowser sprite from Doc Melonhead
Various sprites from Vaati and Paraemon
Custom SFX by Rixitic and Zhark