Illaoi's Dash Can't be Stopped
Tested it with multiple characters such as Thresh's flay, it seems like 'Harsh Lesson' is the only targeted dash that can't be canceled out. Leona, Wukong, Fizz, and Quinn all have very similar mechanics behind their dashes and yet they all can be stopped if you react quick enough with the right ability. So far, it seems like Illaoi is the exception. If for instance a Thresh flays 'Harsh Lesson' back, she just bounces back momentarily before instantly rebounding to land the hit.
Is this a bug?
's dodge still avoids it. I'd imagine
and
can counter it as well. Though I can't remember if it stops the tentacle strike.