One of the gems used in the trapper build I found is the elemental proliferation gem. It says that elemental status effects caused by the supported skill spreads to other enemies. The build wanted me to use 3 of these gems, one on each of the three elemental traps, which is a lot of status spreading. But what does that really do? Could I stack 3 shock stacks up with one spell as as result? Would an enemy with 15 ignites burn for 15 times the damage? This could get silly in a real hurry with big clumps of enemies, especially if the spreading can chain!
I did some research and it turns out the way the gem works makes sense, but is completely counter to how I would have thought it would work. How the gem works is it turns any elemental debuff on an enemy into an aura based on that enemy. Anything that happens to wander into that aura gets the debuff too, but only the base version of it. They don't get an aura as well, so this stuff doesn't spread to cover screens and screens. Shock does stack up quickly this way. If I hit 3 enemies with a single lightning crit then all 3 of them will have a shock aura debuff. As long as they stand beside each other they'll end up with 3 shock debuffs each. (Shock makes an enemy take 30% more damage and can stack up to 3 times... Making all enemies take 90% more damage for a single spell cast is pretty hot!) Ignite does as well, but only the biggest ignite on any given enemy actually deals damage. So all the enemies in a pile will take the most ignite damage possible, but I won't be shelling out a cubed amount of damage.
Frozen as an aura is interesting. Someone who is frozen will stand still and then other enemies who wander up beside them will suddenly get frozen too. In this case the spreading really works out better than expected because I wouldn't have thought new enemies would get debuffed when in fact they do.
Also interesting is the fact that corpses can have debuffs. And those debuffs can be auras. So standing beside a dead shocked dude will make another enemy take extra damage. This is pretty crazy and means enemies fighting on a pile of their friends corpses are potentially in a really bad way. Debuffs last an amount of time based on the damage done relative to the enemy max health. This means a boss won't get a shock debuff for very long normally. But if they had a friend with 1/100th the health then they'll actually end up keeping the shock 100 times as long because the friend's corpses will just lie there giving out a shock aura. Ignite works the same way. Frozen does not, because a frozen enemy shatters without leaving a corpse behind. In fast this will turn off the shock and ignite! So people seem to really hate doing cold damage when using this gem with regular attacks and have to use subpar quivers and such. My spells all do only one type of damage and I alternate them in order to get 50% resist penetration from elemental equilibrium so I don't have to worry as much about this as other people do.
The combination of EE with EP and shock is actually really crazy. Shock is a 'more damage' mod which means it's a multiplicative buff and not an additive one. Resistance is also a multiplicative buff. So assuming an enemy with 0% fire resist to start I'm going from doing 138% damage (I have some fire pen already) to doing 357% damage if I first lay down 3 shock stacks from a shock nova. That is insane!
Normally you need to crit to put a shock debuff up and spells in this game either crit all enemies or no enemies (you don't roll individually per enemy) so getting 3 shock stacks with one spell is normally really easy or really hard. If you crit you get 3, otherwise you get 0. Shock nova, however, gets a chance to shock on it when it's a quality gem. So my shock nova, which is 13% quality, has a 19% chance to shock an enemy and the shocks will last 39% as long. This check is rolled for each enemy which means hitting a big clump of enemies is actually pretty likely to put some shock debuffs up. I'm strongly considering spending the 7 gemcutter prisms needed to put this up to 20% quality in order to have a 30% chance per enemy hit to shock them. Oh, and I have multiple traps on this spell so I actually cast 3 shock nova traps at once which really increases the odds... It's normally hard to hit people with shock nova because it has a huge inner dead zone so anyone triggering the trap won't get hit by it, but my belt makes the traps go off instantly! So there are 3 overlapping circles of shocking goodness!
I love EP on shock nova trap. I'm less convinced I want to keep it on the ice nova and fire traps. I want to actually get this build up to end game and run maps with other people to see how much I care about freezing and burning things. I suspect just being able to consistently lay down 3 shock stacks and 50% fire/cold pen will make people very happy.