Skarner Bug
I don't have any physical proof this happened, but it has happened to me twice now. (Both times I tried to get the recording but I couldn't before it expired..) Anyways, I'm not EXACTLY sure what causes it but I have a theory. First off though, the bug is that Skarner cannot damage inhibitors. I think what causes this is when he uses his E on someone and is ABOUT to stun them but they either die/flash/tp (or whatever) away so you don't actually land the stun but the animation was still started. Both times something similar had happened and then when I try attacking the inhib, skarner uses his "tail" animation like he is trying to stun the inhibitor but it does no damage. Using abilities didn't help, but what DID fix it was actually attacking something. However, the first time there was nothing nearby to attack and I had to wait for a minion wave which wasted a lot of time.
Minor bug, but still can be crucial if you're trying to sneak an inhib.