Corroder

This is a mob that is neutral and won't attack unless you have gear on/out when it attacks it doesn't damage you it takes some durability from your gear. It has a chance to take 5% durability when it attacks. It would be a rare mob and would spawn in the nether and in caves. It looks like a zombie mixed with an enderman, hunched over, have elongated arms and legs, would have horns, would be black and red, and have patches of corruption they would be blue and purple. and when you kill it it would drop items with the durability it took and a bottle of corrosion which would be like poison but for gear.