Cosmic_Castaway
Flying Grayson
Tested it today, against those three characters:I'm pretty sure it's completely safe, actually. If anything is going to punish it, it'd probably have to be either Reptile, Raiden or Kung Lao and only if blocked at close range, if it's punishable at all. I think you can punish with an uppercut if you duck it, actually. Some characters maybe full combo.
Either I, or anyone with the time, will have to test this. But I'm still fairly certain it's 100% safe on block.
Reptile can punish it with b,f+2 (i6)
Kung Lao can punish it with any string from 2. (i7)
Raiden's b,f+3 couldn't punish it, and that's i8. So that leads me to believe the move is -7 on block with pushback.