Does spell vamp apply to all magic damage? I know it works with abilities, but what about applying to magic damage from things like Thornmail, Malady, activated Hextech Gunblade, Deathfire Grasp, and Sunfire capes? Does spell vamp also apply to Damage over time abilities, and Ignite? I know Smite gives Spell Vamp, so I am very curious about all of this.

I'm not entirely sure tbh. I would assume so, but I dont play any champs that really use spell vamp. That said, I believe ignite is true damage and not magical.

Smite works very well with spell vamp indeed. However ignite is not magic damage - it is true damage, which is better, but it doesn't work with spell vamp.

I think it works with hextech and death fire, but don't take it on 100%

Also, on Heim's turrets, I know they don't heal Heim with spell vamp, but someone told me they SHOULD heal themselves, haven't tested this yet though.

ignite technically is true damage, but they havent specified, as i think the tooltip states magic damage that ignores magic resist, which means magical true damage, but whatev

I'd like a definite answer on this too- Because if say Madred's magic damage counts as spell damage, does that mean that Madred's + Rylai's = 30% slow on every hit!? If it does, that's crazy cool, but could also be imba.

Here's the answer guys:

It works with everything that procs Rylai's scepter.

To be more specific: It works with every ability damage (not just magic, but physical and true damage too). Except attack buffs (like poppy's Q, or Nasus' Q).

Summoner spells count too, so Smite for example uses spell vamp.

Madred and other items don't work with spellvamp.