What decides whether you take damage from porcupine on-death spike explosion?

From what I know the spikes are physical spell damage, but for some reason some of my characters can stand in 50 of these without their health bar moving and other characters get chunked for 20% from 1 spike that was fired off-screen. The weird thing is these characters are all very similar in terms of armor, block, health etc.

I was discussing this with a friend and they had the same confusion and experience.

This is what I could find on the matter:

It's an attack and block/evasion/dodge helps a lot

Or very high physical mitigation, or some combination.

But if you are just relying on high life or ES with not much else for defenses against attacks or physical damage, you are really going to get chunked.

And distance matters. If you detonate a whole pack at once from the middle, you're obviously going to get hit by a lot of projectiles. From further out, a lot fewer.

They'll still destroy you even with a lot of physical damage mitigation if there's an added elemental damage modifier on the map.

That's also what makes them dangerous. They just scale very well with elemental damage and additional projectiles/chain.

An old trick was to implement in your CwDT setup, if you have it, an Offering. Apparently, if the Porcupine corpse is consumed, the spike is also consumed in midair. With the right timing you may be able to stop a pack of quills coming through you after the first lands.

With the right timing.

And provided you survive the first quill.

I am a bit baffled to see it's an attack. If that's the case, Evasion-based characters should be able to facetank the little critters with no problem, but I don't recall of any character doing this. If any, they become infamous in all the playerbase and never before I came across a hint like "build evasion" or "blind them". I expected them to be spell, and the "spell_maximum_action_distance" seems to hint this. Though, it could be wrong since there is also an "attack_on_death_%" metadata, so it's clear the naming does not reflect what it actually is...

spell_maximum_distance is just a generic name that is used internally in their code, the important thing is to look at the tags

Evasion characters don't do well against porcupines unless you have a lot of evasion/dodge. A so-so investment into these stats get you killed easily due to most evasion builds not able to mitigate any of the damage.

And lastly on-death effects like this is the main reason why explody chest is so good.