What is the black stuff inside an oyster?

You might be referring to a few things... If it's a black mark / bump or bubble on the inside of the shell, which is not removable, it is known as a "mud blister. read more

If it's a black mark / bump or bubble on the inside of the shell, which is not removable, it is known as a"mud blister." This is a defensive barrier against the parasite (Polydora ciliata) which attempts to bore into the oyster shell. read more

For those who call it oyster poop, they’re wrong. If you want to know what real oyster poop looks like, read this: There I was, covered in oyster poop. read more