Janna has no hitbox I guess :P
Fizz's ENTIRE hitbox went through Janna's hitbox and even slightly under it as well (to account for champion-base touching champion-base) and she was unaffected by it completely.
Fizz's ENTIRE hitbox went through Janna's hitbox and even slightly under it as well (to account for champion-base touching champion-base) and she was unaffected by it completely.