Darius W Bug (5.23)
At the moment there is a bug with Darius' W, that whenever you try to autoattack a champion with it, and it becomes untargetable, you just stop in place until he becomes targetable again. I'm not sure if it occurs with every "become untargetable" abillity but I know it works like that with Vlad's W and Zed's Ult.