Home DIY

We've developed a leak from behind our sink which is weird as it seems the waste part under the plug was made of something that can corrode. It looks like it will be a tricky little thing to replace without moving the sink from the wall which is going to be a bitch. Any idea exactly what this is called?

http://i.imgur.com/17J3RCg.jpg

Its called a waste.

That isn't a joke btw.