Decoy

If Wukong times his decoy before targeted ability reaches him, why does the invisible/actual Wukong still get hit instead of the decoy he left in his place?

I thought that was the whole point of his decoy. Been asking this question for about 5 years now.

I know the decoy will body block Cait's ult, but my decoy got flipped by and invisible me got shot in the face and executed.