A bunch of minor tweaks to Grievous Wounds because I was bored.
Grievous Wounds: Stacks up to 4 times from any source that applies GW, with each stack reducing all forms of healing by 10%. Lasts for 3 seconds, with each new application refreshing the duration.
Ignite: Applies full stacks of Grievous Wounds when a target is ignited, with the full 4 stacks refreshing every second.
Executioner's Calling: Applies 1 stack per basic attack.
Mortal Reminder: Applies 1 stack per instance of Physical Damage dealt.
Morellonomicon: Applies 1 stack per instance of Magic Damage dealt.
Varus: Hail of Arrows' cursed soil now applies a stack of GW every half-second. Additionally, detonating Blight stacks also adds a stack of GW for each stack detonated.
Soraka: Astral Infusion removes a stack of GW from the target, before the healing is calculated. Wish still fully removes GW from all allied champions.
Just random GW-related ideas. I will concede, however, that these changes would be better if Mundo wasn't in such a good spot right now.