I think it's a single indexed bitmap of a 'vortex' texture X-Y repeated and moving across the screen. A piece of code then shifts those color entries in a sequence to create the wave effect.
It works more or less the same as the other animations in JJ1 that aren't sprites.
If anyone's more acknoledged on JJ1's internals and I'm utterly wrong here, then feel free to correct me.
|