Poisson d'Avril!

It's April Fool's and being the francophone that I am, I can't help but think of fish on a day like this. See, in French, April Fool's is called Poisson d'avril, which directly translates as April Fish. Tradition even instructs us to tag people with fish as a joke, as pictured in the following clip-art (the medieval woodcut of the computer age):Of course, the tradition in the DC Universe varies slightly...