>>11897619
Continuing from >>11893590 I've used a similar technique for two gameplay modifiers I'm making for Malice Refined.
The first spawns a ton of exploding barrels on any map (only one of these waves of barrels though): https://files.catbox.moe/98lzcq.mp4
The second makes enemies ghostly and covers the map in fog - both standard Quake distance fog and transparent animated fog cloud objects that appear around the player for extra spook factor: https://files.catbox.moe/8jur2m.mp4
There's also this vampire modifier that probably works about how you would expect, except with orbs of blood flying out of enemies towards the player instead of instant health drain: https://files.catbox.moe/cu1ji0.mp4

I had, unspecifically to this mod, fished for modifier ideas here >>11892875 to no reply, but all of those will be included in the next update to Malice Refined. Still open to any suggestions.