Talk:Fizz/@comment-24431799-20140117043236/@comment-5266525-20140125200440

"I actually searched it, and found out that mr can go below 0, resulting dealing more that 100% of the damage you where supposed to deal."

That's correct, but MPen has nothing to do with this.

Any additional penetration over 100% of your target's MR is simply wasted and does not result in bonus damage.

Heck, without external sources your build could not possibly be reducing targets below zero because MR reductions are applied first.