I specifically refer to Twitch's Spray and Pray, and Shyvana's Twin Bite while in Dragon Form. These both apply on-hit effects to everything caught in them, which had already been a source of monstrous hilarity with Tiamat.
Now that Ionic Spark has been brought to Summoner's Rift, I've been pondering its usage, and it made me curious. Unlike the Storm Shield buff in Dominion, Ionic Spark doesn't have an explicit 4 second cooldown, as it is limited to just auto-attacks. Does this mean that, if I use an attack that hits at least 8 times (a lot easier with a double-hitting Twin Fang, as it were), would two or more chain lightning effects proc simultaneously?
It doesn't feel quite as practical as Tiamat in terms of focusing on the splash on-hit, since the targets of the chain lightning are going to be random when you hit a large enough cluster to take major advantage of the splash. Nevertheless, I'm still curious.