Worked on ranked (solo/duo). Played as a delightfully fed mid Annie in one match, and then in another, when faced against a veigar mid during champion select, I cunningly chose Fizz :p
Spent the whole game hopping over his stun and smacking stuff. Oh: when you use his E, rendering him untargetable briefly, any in-progress spells are essentially made redundant.
That is, if Veigar uses his ultimate (Primordial Burst, Base Damage + AP + 80% of target's AP), and I get Fizz to hop onto his spear, the ultimate will 'fizz' out (lol) but still use Veigar's cooldown. Essentially shuts down his main damage source against me, furthering the popular belief that Fizz counters champions like Veigar without so much as a second thought. :p