How Do Certain Negative Id's Work?

Just wondering what the effects of having negative poison, thorns, reflection, etc. is. It doesn't seem like this would actually do anything...

I know negative poison could be exploited a while ago...

 

Negative poison doesn't do anything related to poison, but it does still have the insane knockback that poison has. The other 2 don't have an effect to my knowledge

 

They subtract from any positive of that effect you may have, say you have +54 thorns, then you get a necklace that has -24 thorns, 54-24=30, you now have 30 thorns. However, you cannot get below 0 in most cases, and if you have negatives but no positives, it will just negate the effect if you get a positive as -34+20=-14.

 

I do believe negative poison used to heal mobs

 

Having negative life steal it will damage you by the amount, I'm not sure if mobs also get healed by it though.

 

Interestingly if you have negative elemental defense like -50 and then -50% elemental defense you get -75 elemental defense