Flywheel questions...

[Chrispbrown36]

So today while I was putting my oil pan back in I look up at the flexplate and notice a shiny spot. This the best way I can describe it.....On the motor side there is what looks like a two prong fork. One of the prongs is intact and I can see that it is welded in place. The other prong is worn down about a quarter inch or so. So, I assume this is part of the flywheel since the one intact side is welded on, but what could be causing the wear to only one prong and not the other?