What exactly is this Lightning thing?

[OSUBuckeye4]

The spawn rate for the fates depends on other fates in the area finishing, so it is actually useful to do a little fate grinding and finish up the others ASAP rather than waiting for them to cycle. I think the crab fate in Middle La Noscea spawns right after the wesp one nearby concludes.

I ended up getting it last night (about 5 minutes before the maintenance began).