Irelia and Guinsoo Blade
I was minding my own business in Top lane with Darius in CS and had 1 kill from jacking the Enemy Mid. I was winning my lane, then we were about level 8 each and she had the Guinsoo Blade as main Item and I had a Black Cleaver and a Doran Shield and we fought. She dealt 4/5 of my hp in damage to me while I only did 1/3 of damage in the span of 5 seconds.
What are your thoughts?