Conflicting news re: King Shark has come out on whether he’ll actually be appearing in the crossover event. CBR claims that in face King Shark would not be appearing in the Arrow / The Flash crossover event. It was David Ramsey, the actor who plays Diggle on Arrow, more than hinted at the synopsis involving King Shark:
[W]e are going to be tracking down a particular member of the Suicide Squad that so happens to be a 14-foot shark
Only time’ll tell we guess. In any case if King Shark does appear again on the CW, it’d be one hell of a crossover event to remember.