User blog comment:Poisonshark/On what not to do with Custom champions, Buff McStrongmuscles/@comment-24795478-20140802172541/@comment-7481207-20140803090740

Nope, the only thing that can hurt you when untargetable is DoTs that are already on you when you become untargetable, which is impossible if you are untargetable all the time. Lux's ultimate, for example, can be dodge with untargetability.