Janna's Tornado can cancel channels too. So you don't have to "waste" your ult on cancelling a channeled ult.
Knocking up in the air wa a guaranteed interrupt for a while, lately I think they changed it cause I've noticed her tornado and cho's spikes not canceling a Kat ult (but that could have been glitches)
Before Q and R interrupted channels, it moved Nunu's ult location. Q and R now interrupts channeling so probably not.
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