Actually I was getting hit with tentacles damage/save itself., not colors I figured it out while trying to zerg multiple groups together and cast Evard's at my feet. Basically my theory is Evard's is a summon spell.
As a summon, it starts off neutral, then swaps to friendly under your control. However, since it has an upfront grab and initial damage on cast, it can process that initial tick before it falls under player control, so as a neutral summon hits everything within it. The other reason you know it is a summons is that it will persist after it 1 shots you.
I learned that in order to avoid this, the initial tick has to be forward cast in front of players on mobs, There's basically no way to save vs. your own DCs, as player saves and player hp was allowed to fall out of proportion to mobs, so if you have metas on you will automatically 1 shot yourself.
As a summons, you may be able to manipulate it with abilities that enhance summons such as PA or Magus mantle, or maybe even force all nearby mobs to run into it to try attack it with pack presence.
I also verified tentacles itself was the culprit by casting it metad on mobs with volunteer melee players engaged (to be clear, they volunteered to be melee, but didn't know about the testing) on them. Occassionally it did initial tick before becoming a friendly summon, hitting all players in range. At 18 without a sentient bonecrusher and a tanky build it was barely survivable by uberpletionists hitting for only 1100 at 18. Got a triple 1100 hit here, with the fighter recovering from it.
Hmm, on second thought I could have probably tested without metas...
On a more useful note, if you lesser globe your multi-boxes, it should in theory prevent the lvl 0 control over the summons, and allow you to mass instakill them to carry them to the end chest.
You will also be able to use this to zerg R6 for pikers, and mass kill them at start and carry them to end in exchange for any SXP in chest. Technically speaking, all cloud effects are conjuration summons, so any of the clouds should be able to be dispelled from player control. This basically means that Magus Anti-Magic burst dispell is going to one shot you with your own clouds, but also that an entangle that heals you via EDs will do so without a self-healing penalty.
