Needs the actual states MT_Spikeball uses in here, along with an explanation that it's assumed that object already has a target when spawned, which is why there isn't anything in there to acquire a target. It would also be nice if someone could look at the code to see what the deal is with the movement lag.
Also, I made some animated PNGs in devmode map view when I was doing all this work, and I figure they might be useful for the page with a little editing(read: cropping(with time still viewable) and turning them into gifs)
Object using A_RotateSpikeball with a speed of 655360(same as MT_Spikeball) for a full rotation. Takes 36 tics. 
Demonstration of the clockwise rotation and target-facing behavior characteristic of actors with negative speeds using A_Rotatespikeball.