This is a disassembly of sprite 34 in SMW, the boss fireball (spat by Ludwig).
NOTE: This sprite behaves exactly like original sprite 34, meaning it is stationary unless its X speed is set by another sprite when it is spawned.
It's Fireball That Ludwig Von Koopa Uses. Description already explainss why it's stationary and what todo. It'll be great for custom boss battles.
It's also usefull for SA-1 users, because original sprite is messed up in SA-1 (source)
Converted to PIXI with SA-1 support.
For some reason this sprite faces you when you get hurt from it, it doesn't seem to be original SMW sprite behavior.