Most OP bug/glitch/exploit you main/s have had?

please include the patch the bug was introduced and if you CAN list the patch it was fixed

it doesn't necessarily have to be a "bug" per say, we can also include some buffs like 5.22 being the reason high number of champs became broken

but as a general rule something that was fixed very shortly after it went live perferably hoxfixed, champion/disabled, or fixed within 1 or 2 patches

for my main,

the most OP bug that ever happened was 5.2 all if nidalee's human skills cooldowns were reset to zero when she used her R to transform back into a human nidalee was disabled until the patch in 5.3 when this was fixed

the second most OP was: invisible spears, now there is a lot of misinformation about this, and riot never actually added it into any patch notes. i know it occurred sometime after 5.2, stayed in effect until at least 5.14, in last season 6 or VERY early season 6. what happened was nidalee's spears would become invisible. obviously what most people didnt know was this was NOT random... it's was explained here (and this video is the person who told riot how to reproduce it) https://www.youtube.com/watch?v=rwX0pheCvmA&feature=youtu.be so basically. anyone who THREW and invisible spear on multiple occasions.. not only KNEW the exploit did it on PURPOSE, but CHOOSE to abuse it and NOT tell riot how to fix reproduce it.