Me and my buddy have been playing around with this pair lately with amusing results. From what it seems, this duo counters mechanics that are wildly popular in the bot lane... The pair significantly punishes mobile ADCs who build their kit around mobility, as well as punishing tank supports that exist to be all over their opponent whether it be a pull, a dash, or both.
Under normal conditions, Singed can't support because he farms WAY too effectively, but Cassiopeia nullifies that because her Twin-Fang last hits WAY better on poisoned targets, therefore allowing them to shove in the lane hard and make the enemy have CS trouble because going-in on them is a rather dangerous action.
There are counters to this however, with Janna and Morgana being the main ones. Janna can keep Singed perpetually CCed in some matter, keeping the running man from running, all while keeping a shield up. Morgana can keep from being burned down with her E while she R,Q, and Ws....
So, what do you think of this duo?
(Note, I answered A to be able to read results.)