Polynomicon - what do?

Ahhh thank you! :)

Or one hit by a Scylla who's behind.

So thats why sometimes you will get two hit by an angry Ao Kuang.

What he said ^^

It makes it so when you use an ability, your next basic attack will not only deal the normal amount of damage, but you will also deal an additional 85% of your magical power in damage. So, let's say you have 500 magical power, and your basic attack power is 100, and then you use an ability. Your next basic attack will deal 100 + 425 damage.
The effect only applies if the basic attack actually hits, so you don't have to worry about missing. However, the effect only lasts for five seconds, so make haste!
Also, protections do apply, the damage from Polynomicon is not true damage, so it can still be defended against by enemy protections.