Found your comment also on the YouTube video 
Anyway I’m stuck at the same step in the process. Using 4.9.1 and I can’t find that one. ( I did skip the sitting and blinking part of the tutorial because I chose to use a custom flipbook for the blinking)
Would appreciate any input on this issue. Thank you!
LE:
Looking again at the video it seems it is a custom event that is created when handling the damage sprites.
It is at minute 28:28 around there, if you haven’t found it already. At that point he creates a Custom Event called Damage System. Good luck