Do you mean the Claw of 'The Noxious Spawn'? If so then mostly people uses for show-off, it looks good at equipment and all that item does is curing your Poisoned state, which means if you're poisoned, right-click on it and it will cure you instead of using "exana pox" spell. You can use it every aprox. 10 secs.
Every time you will equip the item you will get hit aprox. 200hp (depending on your equipment it can be more or less, but note: not in protection zone).
It can be dropped from The Noxious Spawn, the boss of Serpent Spawn, you can face it after completing Grizzly Adam's task, after killing 800 Serpent Spawns.