I'd have to go with icebarrage a spell from the mmorpg runescape.
its an aoe spell that roots you for fucking 20 seconds!!! while dealing 20-40 dmg with a casttime/cd of 1.8 sec. 20-40 dmg doesnt sound a lot? the max hp you can have is 99. so enjoy that thing.
I'd probably have to say jarvan's W
Annoying: Tracer's passive from HotS. Thought Kalista was annoying? THIS IS A WHOLE NEW LEVEL. As for most op spell, well.... I can't decide, but Tracer ult looks pretty powerful. Your's is by far the most op tho
Perfect World International: Blade Tempest. Love hitting 424872 on a full +12 Seeker.
The strongest spell I've seen: Enter the Infinite. Although you could say it's not really from an online game, it can be.
Mend, a healing spell from the MMORPG ArcheAge. Nothing more satisfying than hitting an AoE crit heal for +35k HP (on everybody in a radius of 20m around you)
