Does having negative spell resists do anything?

[Superomegaop 0]

like if your a warlock and have curse of shadows or elements on a target. does going past 0 spell resist do anything like increasing the damage further?

[dDule 0]

I think that it goes to negative, the % that decreases the damage if positive, multiplies the damage when negative. So if it's a negative, you would pretty much give more damage then usual, but i won't say that's a fact. 

[Roxy 8]

In PvE, a mob cant go below 0 resist. 

Dunno if its the same vs enemy players though.

 

Blizzard fixed the negative resist part sometime in the middle of vanilla, previous to that you would do increased damage to mobs below 0 resist

[Undertanker 88]

Stays at zero, however certain mobs have vulnerabilities to certain schools of magic.  

Example would be the tar pits in ungoro, they take a lot of Vulnerable fire damage.

[Superomegaop 0]

what about in pvp? 

[TessTickles 0]

You can't go below 0 spell resists in pvp or pve.

It doesn't exist.